For today's geomorph, I'm drawing inspiration from a gonzo-creepy illustration that Erol Otus did for the Mythos section of the Deities & Demigods (a section that unfortunately never made it into the version that I own).
There is a lot going on in the scene. Since I can't hope to emulate Otus' Elder horror, I'll stick to the room details. The most interesting feature is a stair in the northwest leading both to an exit from the tile and another stair that rises slightly to another archway (I made it into a small room with an evil fountain). The rest of the cavern is full of exits, natural columns, and stalagmites (and countless stalactites which can be assumed but are not shown). Even without the oozing insanity-blasting abomination, this tile would be a great lair for a nasty creature.
The Caves of Cormakir the Conjurer
55 minutes ago