I quickly realized the cave in the void is deeper than 600 meters, my crush depth. And I was chased by three more Ghost Leviathans (It was very hard to figure out the name, just like the Reaper). My Seamoth didn't break that time, but it gave me quite the fright. I traveled past the silent Aurora and found a underwater forest... With mushroom trees. Mushroom trees! I knew this place was strange, but not THAT strange...

***

After exploring that place and getting a ton of Cyclops pieces, as well as Stasis Rifle pieces and Power Cell Charger pieces, I came across another place with huge electric eels and shark-looking things. They don't kill me in one bite like the leviathans, so I was able to scan them both and discover their names:

Electric eel thing: Ampeel

Shark thing: Boneshark

I also called it the Bulb Zone because it has weird bulb-looking mini-tree things. That was when I saw the ravine. It made me shiver and squeeze the Seamoth's controller harder. I went in, and it opened up into a cave with strange green mist that made it harder to breathe when I got out. I immediately got back in, though, because there were more, smaller versions of the Ghost leviathans. But still, I explored, because the whole cave was asking me to.

That may have been a mistake.