Bone caves

It would basically be a new underground biome, that's basically it, But we would have new mobs and new bone items there, like a blue quadrupedal Vixus with bones coming out of its neck, Furthermore, I don't know if I've already mentioned this, but it would be inspired by bird bones, and we would have dungeon-like structures embedded within the biome, and we would use blocks that already exist, such as soul sand and soul soil.