Cheap and sleazy (at least in the continental version) tale of a hypnotist/ventriloquist whose dummy is more than it seems.
Not nearly as bad as its reputation suggests (mainly thanks to the witless Mystery Science Theater 3000), it is admittedly still a cheap little B-movie with some weak performances. Sylvester, especially, seems to be phoning it in. Haliday was a much better producer than actor, but has fun with his role as the evil Vorelli, and there are some fine moments, especially from the underrated Dorne.
The continental version has some minor differences from the US theatrical version, mainly involving nudity, including one sequence where Vorelli hypnotizes a girl into performing a nude striptease.