In the D&D adventure Tomb of Annihilation, Wongo's shrine entrance in Omu (area 12) features two obelisk with monkey carvings. According to the description, they are hanging by the tail.
I've added two version of obelisks, based on the beautiful Obelisk by brimstone326: https://www.thingiverse.com/thing:1477425
Personally I prefer the look of the less accurate monkey hanging by the hand, but the choice is up to you. I've also added the monkey decals themselves so you can fit them to any other obelisk or structure.
The decals are converted svgs based on publish domain drawings
Monkey_Decal.stl | 221.7KB | |
Monkey_Decal_-_Tail.stl | 228.2KB | |
Monkey_Obelisk_-_Combined_-_Hand.stl | 1.0MB | |
Monkey_Obelisk_-_Combined_-_Tail.stl | 1.4MB |