It's Phantasm II.

The two teenage protagonists, Mike and Liz, are psychically linked, dreaming about each other and the horrific Tall Man. As Mike and his pal Reggie drive the midwest in seach of the Tall Man, they see abandoned small towns with razed cemeteries. At the mortuary of one such town, Mike encounters a bogus Liz gagged and covered with a blanket. When he attempts to save her, the demonic beastie pops free from her back, and it has the face of the Tall Man.