Play as a ghost escaped from the Nether Regions, trying to make your way to the surface. You are incredibly frail, but have one advantage: you can possess the bodies of the monsters you encounter. Created for the 2013 7-Day Roguelike Challenge.

Features:

5 levels, each with unique possessable monsters
A wide variety of creature powers
Exploding bodies!
Item-less gameplay
A monsterpedia, which tracks the details of the monsters you possess
Quick to pick up and play
Humorous descriptions
ASCII or graphical modes, seperate for both creatures and the environment.

A sequel, simply called Possession, is currently in production.

Possession: Escape from the Nether Regions screenshots