So I was just looking at Umbreon's pokedex entry for Sun and Moon, and I had found this:
Sun:
When this Pokémon becomes angry, its pores secrete a poisonous sweat, which it sprays at its opponent's eyes.
Moon:
Moon With its black fur, it blends into the darkness. It bides its time, and when prey appears, this Pokémon goes for its throat, and then eats it.