Barbara Crampton in leather lingerie in From Beyond (1986)(3:56)

According to the theory of the scientist Pretorius, man, without knowing it, coexists with another invisible world that surrounds us all the time. The key to entering this parallel world is our “third eye,” an inactive organ in the frontal region. When the resonator (the machine that Pretorius created to stimulate the “third eye”) started working, the scientists managed to penetrate the empire of the “sixth sense” and cause confirmation from the outside: they saw creepy and disgusting creatures around them, gliding in the air! But one of the monsters suddenly became enraged and bit off Pretorius’s head.