C&L's Sat Nite Chiller Theater: 'The First Power' (1990)
It's not one of the all time great ones for sure, but with a too young looking Lou Diamond Phillips playing the good guy and Jeff Korber, as the serial killer turned demon, for a Saturday night, it'll do.
Buffy fans, you may remember Korber playing a psychotic vampire, serial killer named Zachary Kralik, in Sea 3, epi 12. Buffy, unknowingly is temporarily stripped of her slayer powers by the Watcher's Council because she must pass a crazy test for them to prove her resourcefulness.