When I was little, in the early 80's, I saw part of a movie that scared the crap out of me, although it was actually a comedy. It was more or less a spoof of Alien, extremely low budget, and very silly. The crew of a spaceship encounters an alien cyclops made of red slime. They connect it to a translator and it sings a song about wanting to eat people. A doctor assures the others that the alien is harmless, and is immediately devoured by the alien. The movie ends with the alien being sucked into space and floating along behind the spacecraft.
The movie was ridiculous, but I was about 5 years old at the time, and that red slime monster was the monster under my bed for the next several years.