A simple visual guide to the obsidian monolith that turns any and all beings into simians; in it's basic form it can only do that via people passing through its surface to the other side. It "evolves" into the later forms the more individuals it transforms, and the stronger it grows is proportional to its influential aura.

And if a character/creature is already a monkey? Well then that aura compels them to worship and bring it more subjects; as a reward they might be turned into statues made of the same material. Specially chosen subjects will be blessed to be Apeostles, continuing the Apex's work when it leaves for the next world, to start the cycle all over again.

There's alot more to it, but that's the basics, and nuanced research of it never happens, due to any scientists that try being converted~