The afternoon had been quite uneventful for Il Piantissimo in Noki Bay that day.

   After guiding the hero to his certain destiny, which he believed was his good deed for the day, the running man had parted from his charge on the shore by the cliff slide. With Mario and his magic talking water pump off saving the day, Il Piantissimo was left to warm up for their next rematch.

So far it had been pretty quiet, with only a single noki or two showing their faces and the boathouse out of commission. And evidently the hero had not found a way to fix the bay yet, given that the water still ran a dozen shades of violet like a shimmering mermaid's tail. He wondered what was taking so long and if perhaps the hero had found trouble.

Surely nothing he can't handle, Il Piantissimo assured himself.

Which was why he was not so surprised to see the plucky human come sliding into shore from the cliff slide later that afternoon, covered in black goop and grinning from ear to ear.

Jogging over, Il Piantissimo laughed and called out. "Ho HO! So you have returned!" he exclaimed, stopping to stare as the boy picked himself up from the ground after the long plunge. Switching his machine's nozzle, he turned and looked at the masked man in surprise.

"But the question is, where have you returned from??" Il Piantissimo questioned.

"Ah, so you're still around," Mario responded with a familiar snicker. "I've been off doing what you told me. I'm 'saving the bay.'"

"Yes, that I do not doubt, except that I do," the other man replied. "And by that I mean, in case you have not noticed the bay is still lacking in the fresh water section."

"I know, it's a work in progress," Mario snorted as he adjusted his arms around a book he was carrying and turned to the water.

"Well did you find that noki you wanted to see?" Il Piantissimo wanted to know.

"The elder? Yes. Speaking of, you didn't happen to see him anywhere around, did you?" the boy asked.

"He was over there on the shore fishing earlier, I believe," the masked man replied. "Then he got up and left for the cliffs." Pointing up towards the waterfall's source, he shielded his eyes. "A couple of nokis started putting up these ropes across the towers. Perhaps if you are bold enough, you can climb them to the top!"

Huh? Mario gazed upwards at what he indicated. Sure enough, several white tightropes—he couldn't imagine they were clotheslines like those he'd seen back in Windmill Village—were strung over the water high above them, reaching out across the bay from tower to tower. There were perhaps about a dozen of them in all between the three towers and the cliff they attached to. Reaching at all different heights, they suddenly made the entire bay seem very accessible.

   "Hm." Pausing suddenly on realizing what the pianta-man had just said, Mario did a double take. "...Was that a challenge?"

   "For me? Oh no. I am a horizontal challenger only. But you have no problem with heights, I take it, Mr. Hero?"

   Mario squinted at his smart tone. "No, I don't. Now if you'll excuse me, I've got a bay to clear." Stepping past the man to make for the distant tower, he started walking off.

   "Yes! Make it good and clean for our next race!" Il Piantissimo reminded.

   Without turning around, Mario chuckled. "If you're lucky!"

~

   By the time Mario and Fludd had made it back over to the central raft at the base of the green tower, the young noki Aldo had already spotted and flagged them down.

   "Oh, Mario! I was waiting for you to come by," he said brightly as the human approached. "I guess you were successful? Grandpa's waiting for you up top. He told me to send you to him as soon as you returned; he's there by the waterfall," the noki turned eagerly and pointed to the cliff where the cork had been lodged not so long before. "I think you've got a big mission to set out on this time!"

"What do you mean by that?" the human asked quizzically, eyeing the large, spherical bowl the noki was holding.

"Oh, he wanted to explain it to you himself. Don't forget to wear this, though," Aldo instructed, handing over the large container. "You can use this rope as a shortcut to reach grandpa..."

"Hold on," Mario interrupted, turning the object over in his hands. "This is an oxygen tank??"

"That's right! Grandpa said you'd probably need one if you're setting out for the ocean's bottom. Humans need air constantly, don't they?" the boy asked.

Mario blinked, then returned his gaze to the domed glass helmet in his arms. "Ideally yes."

The apparatus was simple but heavy; what appeared to be a multi-layered dome of glass big enough to fit his head inside was sealed off by a thick airtight rubber seal around the neck. A small metal tank that attached to the back and fed into the helmet promised prolonged air support. What have I gotten into now?

"Just slip it on and be on your way!" Aldo said cheerfully. "And don't forget the book."

Mario cast one last skeptical look at the noki. "But I thought the ocean was polluted?"

"You'll just have to go talk to grandpa! Better hurry, he doesn't like waiting!" Aldo urged, shooing him towards the newly-installed tightrope attached to the platform's edge. Clasping his hands, the noki stood back to watch him do his magic.

Somehow, I forgot that fans can be as needy as your enemies, Mario thought to himself. Looking over the device in his arms, he found the front of the helmet and slipped it over his head, hoping it wasn't like a cheap windshield that would fog over with his breath. Luckily, it wasn't: although it felt huge, and it added considerable weight to his shoulders, his visibility was complete up and around. As soon as he pulled it over his head, too, it seemed to conform to his neck and create a seal, locking him in.

I must look like an astronaut, Mario thought, knocking on the surface of his own glass. Sure feel like one.

Trying to look backwards at Fludd—which was ultimately impossible with how big his head was—he managed to hit the machine with his big dome, creating a resounding bong.

   Turning to the promised tightrope, Mario now appraised the climbing situation. The ascension up the cliff he had previously climbed was now considerably shorter, just by way of going straight from point A to point B without taking any winding paths. This way, if he followed the rope, he wouldn't have to touch the cliff face at all.

   The catch was that the tightrope was at a sharp 60-degree-angle upwards over the poison swamp, and there weren't exactly any guardrails.

   "It's a straight plummet to likely death," Fludd observed over his shoulder. "The rope looks to be at least a hundred feet to the top. Watch out for sudden wind gusts."

   "Thanks for the analysis," Mario replied smartly, edging his foot out onto the tightrope. Testing his weight on its surface for a minute, he soon pulled back and got down on his hands and knees.

   "Mario, you don't have to take the rope," Fludd reminded him.

   "No, but it's quicker, and it's here," the stubborn human pointed out, looking around for a good spot to stow the book, not finding one, and finally stuffing it into the gap between his overalls and his shirt. "Whew, that's tight." Carefully reaching out for the start of the rope—which had been bolstered into the stone by a metal clamp on the platform's edge—Mario somewhat awkwardly made the jump out onto the tightrope, clinging to it like a flea. Waiting for the thing to stop swaying, he stared at the magenta waters just inches from his face and held his breath.

   "Do the nokis always travel this way?" he wondered at length.

   "I would imagine so, given their small size and the sheer height of the bay," Fludd responded, shifting his nozzle with a buzz to balance directly behind Mario's head. "I thought you were good at traveling by high wire, anyway!"

   "Ordinarily yes," the human replied as he slowly and shakily got to his feet. Holding his arms out carefully as a balance, he let go of the rope and straightened out, positioning one foot ahead of the other. The rope was thick and wide enough for one foot to comfortably stand.

   "I'm just hauling a lot of added weight," Mario breathed, as if to speak too loudly would tip his balance. Nevertheless, finding his center with little difficulty, he moved his feet forward and started to traverse upwards.

   Fludd didn't miss a beat. "Yes, that would probably be the seafood you had yesterday," he replied.

   Watching the water below grow more and more distant, Mario briefly halted in his tracks. "Wha—No Fludd, that would be you and this big helmet," he corrected defensively. "I've hardly eaten anything the entire time we've been here!" Reminding himself of that, he felt his empty stomach jolt as the rope swayed. "Mm, now I'm hungry."

   "Mario, watch the winds," Fludd interrupted. "They can knock you off in an instant!"

   "I've got it," he replied steadily as he continued along. As they neared the top, Mario could see that the rope didn't lead directly to the waterfall's source, being mounted instead into the rock ledge a short distance down the wall from where he had yanked the cork. From there it was only a short climb to where the noki elder stood waiting.

"See, nothing to it," Mario chirped as he neared the edge and finally jumped off for semi-solid ground. Turning back to survey his climb, he grabbed his visor and grinned. "That might be the longest high wire I've done yet."

"Where did you learn to do that?" Fludd wanted to know. "Did you used to perform with a circus?"

   "Ha, not quite," Mario chuckled as he hauled himself over a stone step. "It's just another one of those things you have to pick up on the job."

   "Perhaps you should audition for something," the machine suggested.

"Like what?" his owner snickered as he walked towards the noki, who spotted him now and waved with his pole.

"Like a circus," Fludd replied.

Mario almost stopped because he was grinning so hard. "So let me get this right, you think I should use my jumping and athletic skills to join a circus?"

"Well, not if there are more pressing things to do." Fludd didn't see anything amusing.

"Sure. Things like, rescuing people from monsters and cleaning up vandalism and having a peaceful vacation," Mario suggested.

"Of course," Fludd agreed.

Mario knew he must have been smiling ear to ear as he approached the ledge overlooking the waterfall. The elder, peering intently over the side into the sheer drop where white water plummeted down a hundred feet or more, took up his usual practice of neglecting to look up.

"I've got it!" he announced as soon as the boy's footsteps were heard behind him. Puffing up his chest and looking at the gushing water in satisfaction, he nodded. "Yes, I surely do have it! What have I got?"

Mario glanced around in uncertainty. "Um, the book you asked for...?" he suggested, pulling it out of his overalls.

"No! ...Oh, well, yes, I suppose so," the elder acknowledged, turning to him at last to receive the old tome. "Yes, very good, Master Mario. You have our people's thanks!"

The human cocked an eyebrow at him.

The elder cleared his throat, flipping quickly through the worn pages. "But that's not all! Why, I have the answer to our polluted ocean problem, of course!" he exclaimed, suddenly stopping at one place and pointing harshly to the page. "And the answer is you! You must go to the ocean floor!"

Now Mario stepped forward. "Oh yeah, Aldo down there mentioned something about that," he said pointedly. "Said I'd need this—

He tapped on the glass of his helmet as if it was an ugly eyesore. "What's going on?"

"Ah, perfect! So you're almost set!" the elder praised.

Mario was stubborn. "Set for what?"

"Well, like I said, you must go down into the sea floor. Of course, that is impossible for you ordinarily, because you require air," the noki went on. "Therefore, I took some precautions to get you that helmet! Wear this and you can stay underwater for much, much longer."

"How much?" the boy asked curiously.

"Oh I don't know. It's not a huge oxygen tank, so I would say a few good minutes. Don't go wasting your air."

Mario frowned uncomfortably.

"Anyway, I imagine you can use your fancy jet pack there to move around through the water much faster," the elder continued enthusiastically, turning back to the book now. "Now are you ready? You look like you're ready."

"But what am I supposed to be doing down there?" Mario asked. "I thought the water was dangerous anyway!"

"Aha! That's where we were wrong!" Coming over to share the book with him, the noki elder pointed to a handful of weathered sketches on one page. "While you were gone, I saw the real culprit. And this book confirms it! The gunk in the ocean is caused by..."

Mario found the suspense irritating.

"...a giant eel!"

Now Mario was engaged. "Really? You saw it? How big?"

"Yes, it looked enormous, I tell you! From what we could make out," the noki amended. "But as I suspected, the noki people have been plagued by such things before. I don't know if this is the same eel, but now it seems it's moved into our ancestral home at the sea floor."

"So you want me to chase it out," Mario figured.

"Well, yes and no," the elder replied. "I don't believe it is of angry intent, since it has done nothing truly destructive."

"At least not until you're close enough to eat," the boy remarked, wide-eyed.

The elder didn't note his cynical tone. "I'd been hoping the ancient nokis left some clues as to what would drive the eel away or how to stop it, and I think I've found the solution," he went on, studying the book carefully. "So, that purple poison is all over the surface, but I have reason to believe that since it seems to be rising from below, it has settled into a layer on top. And therefore, the bay should be clear underneath!"

"Isn't that... a bit of a stretch?" Mario asked, crossing his arms.

"Perhaps. But according to the old accounts, it's true! They said that the giant eel, which they called Eely-mouth, had been nursing some nasty cavities down there. And his infestation got so bad that he polluted the entire bay!"

"...That's not the most normal thing I've ever heard," the human remarked.

"Well I think it's true. And it's not going to get better until we fix it!" the noki replied.

"I can see where this is going," the boy stated.

"The newly uncorked waterfall created a gap in the pollution that you can use as an entrance!" the elder said, pointing back to the waterfall. "It'll carry you right on down to the Deep Sea of Mare! Just jump right in there!"

Mario raised his eyebrows. "So you want me to ride the jet stream and go right into that eel's mouth, to clean its teeth?" he summed up.

"Yes, I think you've got it," the noki replied. "Doing so will ease his pain, and he'll return from whence he came! No doubt about it!" He slammed the dusty book closed.

"You got all that from the tome?" Mario asked incredulously.

"Eh, somewhat. Now, gather your courage and DIVE!" He swung his fishing pole around and almost flung it into the waterfall by accident.

   Mario wanted to be amused, but he was fully aware that the noki was serious. Once again, how do I get into these situations. Feeling his air helmet to make sure it was secure, the boy put up his hands appeasingly.

   "Alright, alright, I'll go," he said. "But... if you're wrong about this, I hope you have a backup."

   "Well, I can brainstorm with my fishing pole, but I think you're probably more practiced at improvising than I am," the elder replied nonchalantly.

   Mario groaned inwardly at this, but he didn't respond. Stepping past the noki to look over the very edge, where the cliff jutted out into a small, diving-board-like platform, he stared downwards into his destination. The roaring waterfall rushed in a white mist past his shoulder and disappeared into the bay below, obscuring the purple waters where it breached the surface. From what he could see, which wasn't much through the thick clouds of water droplets billowing around the falls, the bay at impact point seemed clear.

   Without looking back at the old noki, who was watching him from behind with irritatingly eager anticipation, Mario took two tiny steps backwards. He was just about to do it, too, when he suddenly remembered something and dropped to his knees.

   "Wait a minute! If I'm going to move around under there I'm probably going to want to switch to the hover nozzle," he realized, quickly removing Fludd for the swap. Behind him, the elder sighed in impatience.

   "Yes yes, are you good now? Eely-mouth is waiting!"

   Taking his sweet time, perhaps just to be irritating, Mario grinned as he unscrewed the rocket nozzle and reapplied the twin hover nozzles. Finally replacing Fludd and fastening the belt around his waist, he stood and shrugged.

   "I know. I've been waiting for things too!" he said. Then, without delaying a second longer to hear what the man might have to say, the human took a deep breath, wheeled around to the edge, and jumped headfirst over the cliff.

   Gravity hadn't been so real in quite a while.

   Unlike when he was sliding down the steep cliffs or hitching a ride on a giant bird made of sand, Mario's descent was a wide-open free fall of over a hundred feet to the thundering mists below. Leaving the elder and the cliffside and the entirety of the dry land behind him, he spread out his arms and tried to position himself into a clean dive as he sliced through the screeching air. For a brief second, he seemed suspended in time.

   Mario remembered, at that moment, why people so often cautioned against jumping off cliffs.

   He also remembered, as his view was obscured by the white foam, how this had to have been at least the third time he had done it recently.

~

   The water was warm. Not too hot, not too cold; perfect for small semi-aquatic creatures to make their homes within.

   As the tiny human breached the water's surface, being immediately caught and pushed downwards by the powerful falls, he had to resist the instinct to hold his breath. Paddling furiously so the waterfall would carry him downwards, Mario glanced around inside his small air bubble. The water had closed over his head some moments ago, and now the jet stream was beginning to lose its force. Turning his attention downwards as he began to slowly sink to the depths, Mario felt for Fludd's handles.

   The bay, even as it sat beneath an ocean of pollution, was enchantingly beautiful. Softened white daylight filtered into the depths through the cloudy layer of lilac poison above, somehow managing to fill even most of the undersea caverns with enough visibility to explore.

   As the area opened up before his eyes like another world, Mario felt his breath leave him for a brief second. From where he floated, he couldn't even see the bottom before the bay gave way to blackness below; nevertheless he could see enough to be impressed. All the things he'd heard mentioned about the Deep Sea of Mare and the underwater city came racing back to him, leaving him in a momentary silence.

   All around him—he suddenly realized he must have descended underground—sheer stone walls rose towards the surface like an enormous sinkhole had swallowed him up. Even from there, Mario could see the gray walls lined with countless windows, holes and tunnels in the rock, giving the entire bay the appearance of an old long-abandoned city.

   Whoa... they must live in these caverns! he thought in awe, twisting around a little to get a view of the whole scene. Although the cliffs enclosed him on three sides, off to one direction they opened up into what appeared to be an underwater canyon, as if it were a city street lined with skyscrapers. Giant pillars that reached beyond Mario's field of vision stood about in various places like watchtowers, engraved with faded symbols. Reaching across gaps and connecting the different carved 'buildings' that wrapped around cliff corners, giant stone bridges arced over the traffic ways, reminding Mario a little of the Colosseum. The domed windows and doors in the architecture further enforced the ancient feel of the place.

   That was when he remembered his voice. "Fludd, how's it going back there?" The sound of it, which was hollow and obnoxiously loud within his air dome, seemed to have no problem reaching his backpack.

   "A-OK, Mario," Fludd replied, metallic voice coming muffled through the water. "Are you alright?"

   "Never better," the human shrugged, scanning his surroundings. "Fludd, are you getting anything? Why's the city empty?"

   "I suppose they have all fled," the pump replied. "I do get strange readings, but they are competing with interference. We must be a good deal below the surface."

   Kicking his feet a little, Mario looked downwards. Although he could still see nothing but a kind of encompassing blackness below, he couldn't help getting a strange feeling the longer he stared.

   "How about the water quality? Is this stuff safe?" he breathed against his glass, inspecting the skin on his arm to ensure it was intact.

   "My analysis indicates that it is," Fludd replied as his owner swatted an arm against the invisible substance. "The toxins above do appear to have settled on the surface after rising—

   "Wait," Mario cut him off. "Fludd are you seeing that? Below?"

   The pair looked downwards to the hidden abyss. There was nothing obvious, at first, about the hole that begged attention; then Mario spoke again.

   "There's movement. I can feel it."

   "Feel?"

   Mario didn't blink. "It's gotta be big. It's the eel, he's here," he said with a calm urgency that Fludd found concerning.

   "Eely-mouth? Are you certain?"

   "As certain as I can be when I've been in eel-infested water before." Mario wrapped his hands around Fludd's handles.

   There was a brief pause as he continued watching the hole, Fludd scanning the vicinity. Now he could definitely see motion: beyond the upwards-swirling bubbles that spun past him, Mario could now make out something colorful and glowing below. As he stared a bit longer, he thought it looked like a couple of pairs of glowing golden eyes in the dark.

   "My sensors show highly toxic materials approaching," Fludd observed suddenly.

   Mario set his eyebrows in determination. Eely-mouth. "We need to get closer," he said.

   "The gravity is subdued, but with time you will sink," Fludd replied. "Watch out for those dark globules—I believe that is the poison."

"These things?" Mario asked, pointing to a large plum-colored bubble rising past his head. In the water, which seemed to get dimmer as he sank down, it almost appeared as an orb of dark energy.

"Whoa. It's almost as big as me," he marveled, flutter-kicking out of the way. Listening to his own voice bouncing in the enclosed space of his helmet, Mario almost frowned. It feels so weird to be able to talk underwater!

"It looks like they rise to the surface and disperse their toxins there," Fludd observed over his head. "Watch out, there's more!"

Snapping his head down—at least as far as he could—Mario danced aside as a wave of the purple bubbles came swooshing upwards past him. "Boy, these things are going to be a... how do you say it? Thorn in my side," he remarked.

"If these are the thorns, then that's the thicket," Fludd said in a tone that made Mario pause. Twisting around, he blinked downwards.

"What's..."

He didn't finish. He didn't need to finish, primarily because the trouble in question became visible to him all at once below his dangling feet like a waking terror.

[There should be a GIF or video here. Update the app now to see it.]

Mario inhaled slowly before he remembered to move. "Mama mia, that thing's huge!"

"Mario, the hover nozzles!" Fludd reminded him urgently.

For the first second the human didn't respond, being too entranced by the beast of the bay to care. The creature called Eely-mouth was aptly named, primarily because at first it was all Mario could see: an enormous mouth. Wider than a dinner table, gaping like a sinkhole in the middle of the desert, a huge, cavernous pit opened up in the darkness below him, revealing two rows of faintly white teeth the size of boulders. From it instantly came a wash of dark bubbles that threatened him off, some tiny and others almost enormous.

Even through the water and his helmet, Mario heard the low, rumbling gurgle that emitted from a giant throat.

"Yeah... I think you're right," Mario muttered under his breath, fumbling for the hover nozzle without taking his eyes off the creature. Finally succeeding in switching it over, he grabbed the handles and gunned himself upwards.

Mario had used Fludd underwater before, but never had he realized that the hover jet pack, while completely submerged, could be so mobile. Carried by the force of the twin jets, the duo suddenly seemed to skyrocket into the air, spiraling in a torrent of bubbles through the water above. Aiming for a nearby stone bridge, Mario tried to bring them out of harm's way so he could land.

"It seems we are being attacked by plaque-forming bacteria," Fludd observed as the human reached out for the ledge with his feet. "The elder must have been right!"

Mario snorted, turning back to stare into the murky depths. "So what, I have to go into its mouth and... wash it's teeth?"

"If you are interested in helping, I believe so," the machine responded. "My hover jets should be powerful enough if you can get low enough. Perhaps it is in pain."

Mario let his shoulders drop as he and Fludd watched the cavern floor below, which he was now low enough to make out. The city walls sloped gently into a large, otherwise empty crater on the sea floor—otherwise because it was currently inhabited by an enormous visitor.

As the toxic bubbles cleared for a moment, they finally had a clear glimpse of the monster; and it was certainly a shocking sight. Slick black scales shimmered and hid alternately in the darkness. Two pairs of glowing orbs, each the size of dinner plates, flashed prominently on either side of the creature's mouth, leaving it a complete guess what the eyes were. Squirming in what must have been a giant tantrum, an absolutely huge eel—part worm, part hippopotamus by the shape of its mouth—erupted like a geyser from the crater, sending sand clouding in every direction. Half-emerged, writhing in obvious discomfort with its snapping teeth reared up, the oblong creature looked like a nightmarish shape from fiction.

Mario's breath caught for a second as he stared. "If I was someone else, that would be utterly terrifying," he said.

"But you're Mario...?" Fludd prompted.

The boy hardened his gaze and nodded briefly. "Let's do this." He pushed on the hover nozzles and let it lift his feet from his perch.

Reinserting himself into the fray was no challenge, since Eely-mouth was still spinning and thrashing in the ground like a giant food processor. Blasting himself into the stream of oncoming pollution, Mario allowed himself to hang in wait for the creature to thrust upward again.

Watching carefully for the poison bubbles, he couldn't help making side comments. "...Does he have four eyes?? Or are those even eyes?"

"Mario, get ready!" Fludd announced.

Fine, we'll marvel at exotic species later, the human snorted to himself.

Mario was no stranger to eels. Or undersea caverns, or large aquatic creatures in general. He didn't want to be critical of the astounding sea snake before him; he just knew, all too well, how unexpectedly dangerous such animals could be. They could be equipped with hidden electric charges or concealed sharp teeth, or perhaps even worse, enchantingly horrifying skin that seemed harmless as rubber until one brushed it to find it coated in tiny barbs. At the nasty thought, Mario rubbed his arms protectively. Let's NOT do that today.

Coming back to the present, he looked back to the eel to see the huge festering mouth opening fast beneath him. From his view near the giant muzzle, which was definitely too close for comfort, he could see that there actually didn't appear to be many teeth—maybe only a dozen or less. While visibly worn with gunk and who-knew-what-else, it wasn't an impossible job.

"So this is what's clogging up the bay's water?" Mario asked incredulously.

"Easy... that's it," Fludd guided as he slowly allowed himself to float down closer to the teeth's level. Just when he was within biting range, Mario concentrated on the one nearest him and let his jets fly.

"Careful, you don't want to go taking off," the pump coached him over the swooshing of water and the soft growl of the beast, who was being surprisingly still. "Hover low. I think it is working!"

"Okay, tell me when to move to the next one," his owner grunted. I wish I could say this was the weirdest thing I've ever done.

They managed to clean, at least according to Fludd, almost three of the eel's incisors (or whatever they could be called in such a creature) before Eely-mouth suddenly let out a trembling howl, jerking violently. Reacting quickly, Mario jammed down on his jets, but he only missed the eel's flashing jaws by inches. Rocketing to a safe height, he watched as Eely-mouth retracted backwards into the ground a bit, sinking into the sandy bottom like a slug to hide.

   Confused, Mario breathed, "Are we done?"

   "We can't be. He's probably just taking a rest," Fludd figured. "He was being very patient with you!"

   "Wonder if he knows we're here to help," Mario mused. Keeping a steady hand on his jets, he maintained a good distance from the eel. At least there's no worry about running out of water, he thought, feeling the hum of Fludd's turbines churning gallons through his system. The hover nozzles were very good for underwater movement—perhaps the best Mario had ever had—but the water still offered plenty of resistance to free mobility. It was why working underwater always made Mario a tad more cautious; one could never react quite as swiftly as on land.

It was especially weird to have full mobility of his head but not the rest of his body. Mario had swum in a few tricky situations in his day, and this was admittedly the first time he'd done so with any kind of breathing apparatus. It was a nice change, although the bulbous size of the thing was annoying.

   Guess I have too big a head, he thought with an absentminded snicker.

   Bubbles fizzed up around his legs as he kicked upwards a little, activating his jets to disperse the poisonous toxins still rising around him. As the violet venom billowed away, Mario suddenly frowned.

"Hey Fludd... is it just me or is the air a little light?"

"Hard for me to say, Mario," the machine gurgled through the water as Eely-mouth began to resurface from his hidey-hole below them. Shaking the underwater caverns with a deep, muffled roar, the black worm once again opened up his giant hatch to reveal his not-so-pearly whites.

"Look, he's waiting for you! Now's your opportunity!" Fludd exclaimed.

Nodding slightly, Mario waited for his body weight to carry him down, down through the bubbles and poison to the mouth of his waiting patient. Thinking of it like that, he almost chuckled to himself. Ha, patient. This is almost like the time I crawled in that whale's mouth—

A sudden jolt from Eely-mouth distracted Mario from his thoughts momentarily... until he took a deep breath and found it not-so-deep. Ceasing his hover nozzles for a second in surprise, Mario tried a gulp of air. Uh oh.

"Almost there! My, that was a bad one!" Fludd remarked in awe, seeing as the tooth they had hit was so decayed it had dislodged, sending it floating off entirely. Swerving to the side to avoid it, Mario was barely paying attention to what he was doing.

"Fludd... I think my air supply is getting low," he breathed heavily.

"Oh no. You will have to resurface," the machine replied simply.

"But we're so close," Mario responded, returning his focus to the eel below. "Hang on... I've got..."

Why am I talking? I should preserve air. Clamping his mouth shut, Mario tried to intake as little air as possible to complete his work. The feel inside his helmet wasn't horrible, but it was definitely starting to get stale.

"Mario, you should not stress yourself," Fludd began his spiel. "If you hold your breath for just a few minutes your lungs may—

"Last... one," the boy panted, powering himself over to the final tooth. As the jets shot downwards to finish off the eel's bacterial problems, Mario felt a sudden wave of heat come over him. Ohh... really should get to dry land soon...

His efforts, meanwhile, had seemingly paid off. With the completion of the last dirty tooth, Mario was able to back out of snapping range, leaving Eely-mouth free to chomp as he pleased. Stretching upwards towards the light, he made clearly visible his new set of flashy teeth.

Mario could see his success; he could see the yellow glowing eyes blinking slowly in an eerie way on either side of the enormous mouth. He could even see the giant eel begin to wrestle itself free from the ground all at once, as if suddenly realizing it was well enough to get up and move again.

For a moment that utterly startled him, he stared and watched as a new and toxin-free Eely-mouth emerged like a mountain from the earth, powdery sand cascading in waterfalls down its seemingly endless ebony scales. With a strange little grunt that echoed through the cavern—or so Mario thought—the enormous dental patient unearthed himself from the sea floor, revealing a massive body that was several buses long; then, with what could have only been a gurgle of thanks, Eely-mouth turned tail and swam away, making straight upwards and towards the open sea that would come beyond.

"Remember to take proper care of your teeth!" Fludd said to seemingly no one.

"That's pretty low on my list of priorities," his owner rasped. Sinking down deeper to the cavern floor, Mario couldn't help watching the creature go until it was well out of sight. You're welcome, he thought, not bothering to speak out loud. Gazing in awe for a moment at the giant overhanging shadow of the creature that fell over him, he almost didn't notice at first that his hearing was starting to fade out.

   Whoa... Oh boy, that's probably not good. Glancing around briefly, he noted that he had almost touched the bottom floor of the bay now, with the gray sandy surface only feet from him; he could feel the change in pressure pressing on his head. He attempted to inhale for more air but it came back hot and empty.

   Fludd... I'm really not getting much oxygen here, he thought absentmindedly, feeling around for his handle. That's when he had a brief second of clarity.

   Oh yeah, Fludd can't hear my thoughts. ...I can't hear Fludd. Blinking rapidly to avoid the loss of consciousness he knew had to be coming soon, Mario looked about him in a circle. Ow... The horror, he thought, feeling every muscle in his chest begin to burn in protest. Wouldn't it be bad if... shine!

   Semi-forgetting his troubles in a sudden bid for reward, Mario lunged through the water towards the sparkling golden spot he abruptly spied, half-covered in sand as it lay hidden beneath the place where Eely-mouth had been. Catching the prize close to his chest without even bothering to look at it, Mario briefly wondered if Eely-mouth's trouble had anything to do with a certain rotten koopa.

   Nevertheless, it didn't matter now. He had already felt that dull, icy feeling he recognized from his long repertoire of near-death experiences, and it didn't leave much time for speculation: he needed to go, and now.

   He was aware that Fludd couldn't get him out of there on his own. He was aware that it would be a new, terrifying experience if he should meet death so suddenly; he was aware how sad it would be—how devastating—to those who knew him, if he should never return; and worst of all, he was aware of the horrible fate the princess might face if he should not.

   But Mario didn't lose his calm. He had juggled with his life many times before, and this, he was sure, would be merely one more slightly sticky situation he could chuckle about in the future.

   Golden treasure clutched tightly, Mario finally grabbed Fludd's handle and rocketed his hover jets upwards, racing yearningly towards the bay and the light high above.