The Evil on AllMovie

This superbly chilling haunted-house opus stars Richard Crenna as a therapist who, with wife Joanna Pettet, selects a lavish mansion for use as a drug rehab clinic. No sooner have the staff and their assistants set up housekeeping when a nightmarish force emerges from a trap door in the basement, and the house begins preying on the occupants in horrendous ways, from freak electrical bursts to sudden flash fires (leading to some extremely graphic scenes of people being burned alive). Director Gus Trikonis keeps the tension unbearably high and drives the plot on the strength of an excellent cast -- especially Victor Buono in a magnificent but brief role as the Devil himself. Amazingly, some prints of the film deleted his appearance altogether.