Hi, here's a new feature for ocean caves I came up with, since caves are being updated and this would be a good time to suggest it. This one isn't a new biome, but rather a new variety of coral, the Twisty Coral.
Twisty Coral acts the same as the other types of coral. It has Fan and Block varieties, which can be dead as well. The blocks spawn in spike shapes that wave and point upwards, like how the regular sized one is. All in all, it's just another type of coral.
Unlike the other types, however, Twisty Coral is almost invariably found in caves. A few might be found in reefs near the surface, but that's quite rare to find. Large block structures spawn somewhat uncommonly in underwater caves above Y=20, statistically, with the regular and fan types scattered around or sometimes on their own.
Wandering Traders have a chance of selling types of Twisty Coral, which is lower than other types due to their rarity.
Just a tiny addition to ocean caves, nothing major.