From Beyond

An obsessive scientist Dr. Pretorius (Ted Sorel) and his assistant (Jeffrey Combs) have invented 'The Resonator', a device designed to stimulate the brain's pineal gland and expand the powers of the mind. The machine gives them more than they bargained for however when a parallel universe inhabited by slimy creatures ready to prey on humans reveals itself. Pretorious meets a sticky end, returns as a grotesque, deformed being and all manner of depravity ensues. Based on another H.P. Lovecraft adaptation.