MST3K Ep. 106 - "The Crawling Hand"
An astronaut's capsule crashes in the ocean and his severed hand (controlled by an unknown alien force) washes up on a beach, where it's found by a moody teen.
Soon both are on respective rampages. Includes Alan Hale, Jr. (Skipper from Gilligan's Island) as the sheriff and Peter Breck (Nick Barkley from The Big Valley) as a NASA investigator.