aka The Possessed, aka Nightmare at Blood Castle
How bad is it? Over-the-top, fairly well-filmed, but utter trash.
Should you see it? Yeah, this one's okay, if not special.
A mental hospital in the middle of a desert (which looks like a miniature golf course) is run by a mad doctor who experiments on (i.e. tortures) patients. Those that die get dismembered by a hunchback assistant to fit in coffins; one girl gets put live in a coffin along with snakes. One experiment led to a monster in the basement which looks like red licorice whips or maybe a bloody mop blown by a fan. The usual parade of unsuspecting innocents get brutalized. It's all very tacky and has some wondrously saturated color, but it also is reminiscent of Al Adamson's "Blood of Dracula's Castle," which is not a good thing.