A sponge-like tree (tree-like sponge?) growing on the ocean floor.
An alternative tree style growing in the caverns.
While swamp bushes like these are possible in the vanilla tree configuration, they are limited to the world's surface. With the unlocked tree feature, similar bushes can be placed on the shores of underground lakes.
A taller sponge-like tree.
These trees have a low luminance so they can be seen against the dark cave background.
