Ootkins are the ghosts of Terrahypt. They mostly stem from Peukins that have passed away after a relatively long life. Ootkins are mostly harmless, as they cannot directly interact with their environment. But if a person gets close to one, the Ootkin can interfere with their brain and cause violent hallucinations.
If one does not avoid contact with the Ootkin for a longer period, they can lose sanity and may become possessed. This usually means death for the host as the Ootkin does not know how to use its body, mostly by not being able to breathe or eat.