Zaat is a 1971 American independent science fiction horror film produced and directed by Don Barton, and co-written by Barton, Lee O. Larew and Ron Kivett. Produced on a $50,000 budget, the film stars Marshall Grauer as a mad scientist who aims to transform himself into a mutation to seek revenge on those who spurned him.

Critical reception has been predominantly negative, with criticism directed at the film's script, acting, and poor monster design. Cited as one of the worst films ever made, it gained significant exposure when it was used in an episode of the movie-mocking television series Mystery Science Theater 3000 in May 1999, under its alternate title Blood Waters of Dr. Z.