I could have sworn...

...that this film was a complete rip-off of House on Haunted Hill. They have so much in common [spoilers for both]: a husband trying to kill his wife; characters faking supernatural activity to drive someone else insane; a climactic sequence involving a skeleton representing a dead spouse; a weird cacophonous score composed of wordless female vocals. Also, the "free coffin if you die of fright" segment at the film's beginning feels like something William Castle himself might have come up with.

Only hole in that theory is that this film was released a full year before House on Haunted Hill. Since they both came from AIP, maybe some executive or producer vaguely remembered elements of this film and had it worked into a Vincent Price vehicle or something.

Oh, no, I'm not tired. But my finger is!