Fiend

In the 1980 film Fiend, Don Leifert stars as Eric Longfellow, a music teacher who returns from the dead to terrorize his suburban neighbors. After reanimating Longfellow's corpse, an evil spirit forces him to strangle and absorb people's energy to stay alive. When Longfellow moves to Baltimore, his neighbor Gary Kender (Richard Nelson) begins to suspect something is amiss with his new neighbor.