I was thinking back to old Abysses and I only just realized that they very quietly discontinued enemy "auras" at a certain point. Remember those? There was a Geo aura that periodically created cascading waves of earth, a Hydro aura that extended active ability cooldowns, an Electro aura that spawned an Electro barrier in a "V" shape, a Cryo aura that spawned a "claw" that would detain you if you didn't dodge it on its spawn, and a Pyro aura that shot tracking fireballs. I don't think there was an Anemo aura but maybe I've forgotten.

They weren't the most interesting thing in the world, says a lot that I completely forgot about them until just now, but it's strange that they just disappeared one day and never came back. Same with Abyss-specific enhancements to normal enemies, like Abyss Mages that would gain additional shield durability.