dyb·buk 
(dĭbk, dē-bk)
(dĭbk, dē-bk)n. pl. dyb·buks or dyb·buk·im (dĭ-bkĭm, dē′b-kēm)
In Jewish folklore, the wandering soul of a dead person that enters the body of a living person and controls his or her behavior.
[Yiddish dibek, from Hebrew dibbūq, probably from dābaq, to cling; see dbq in the Appendix of Semitic roots.]