The Dybbuk are a fictional race created in 2009 by Chaosium for its Call of Cthulhu RPG.
The Dybbum are a race from an alien planet whom have a gaseous form. They arrived on Earth, millennia ago, fleeing the mi-go. Where they discovered they were unable to complete the simplest tasks but if a human inhaled them, their consciousness could replace that of the host. Though reluctant to abandon their hosts, occasionally one is convinced to do so. The host has no recollection of its possession.