Laserblast Trailer (1978).
Laserblast is a low-budget 1978 science fiction film. It stars Kim Milford as "Billy Duncan" and Cheryl Smith as "Kathy Farley", and is notable for Eddie Deezen's debut (as "Froggy") and for a four-minute cameo by Roddy McDowall as "Doctor Mellon". The plot involves a constantly put-upon young man's discovery of a laser cannon, his ensuing rampage after continual exposure to the weapon's radiation mutates him into a wild, destructive lifeform, and his eventual death at the hands of the aliens who left the cannon behind on Earth in the first place.
Plot:
Loner teenager Billy Duncan (Kim Milford) stumbles across a lost alien ray gun while wandering the desert one day. Billy uses the destructive weapon to get revenge on his enemies, but quickly finds himself beginning to turn into a violent, alien creature who destroys anyone who offends him.
Alternative German title: Laserkill – Todesstrahlen aus dem All.