When a player ends up inside any of the leaf blocks added by this mod (such as when riding a horse), and when entities end up inside the leaf blocks, they end up suffocating and taking damage from it as if it was a solid block.

Here's a video showing it:
https://github.com/dayofpi/super-block-world/assets/160932138/ed14d4cc-fcc0-4534-882b-43d4f905797d

Here's some screenshots of it as well:

MC Version: 1.20.1
Forge: 47.2.0
Super Block World Mod Version: 0.0.8-1.20