I think you mean "dybbuk". Wikipedia has this to say:
In Jewish folklore, a dybbuk is a malicious possessing spirit, believed to be the dislocated soul of a dead person. 
"Dybbuks are said to have escaped from Gehenna (a Hebrew term loosely analogous to the concept of hell) or to have been turned away from Gehenna for serious transgressions, such as suicide, for which the soul is denied entry. The word "dybbuk" is derived from the Hebrew ??????????, meaning "attachment"; the dybbuk attaches itself to the body of a living person and inhabits the flesh. According to belief, a soul that has been unable to fulfill its function during its lifetime is given another opportunity to do so in dybbuk form. It supposedly leaves the host body once it has accomplished its goal, sometimes after being helped."