TerrorVision

TerrorVision is an American horrorcomedy film released in 1986.

On an alien planet named Pluton, an alien garbage disposal converts a monstrous mutant called a Hungry Beast into energy and beams it into space. Meanwhile on Earth, the Putterman family is getting satellite television, courtesy of a temperamental DIY antenna. The reception is poor at first, but suddenly strengthens when a bolt of the alien energy hits the dish.The little boy Sherman Putterman and his exmilitary, survivalist grandfather enjoy a night of horror films hosted by the buxom Medusa, while Shermans parents go out to meet some swingers and his sister goes to see her boyfriend, named O.D. Sherman and his grandfather eventually fall asleep, but are woken when the Hungry Beast materializes out of the TV and eats the grandfather. Shermans parents arrive at this point with swingers Cherry and Spiro, and lock up Sherman in his grandfathers bunker. There, the Beast imitates the old man in order to fool the boys mother into thinking it safe. ........

Source: Wikipedia