What I remember from seeing this on HBO when I was a kid is that it's kind of an Alien spoof. A ship full of people lands on a planet to check it out for one reason or another. One of the guys says "Ifound some jelly." and shows everyone a little pink blob on the end of his finger. When taken on board the ship, the blob grows into a monster which proceeds to eat its way through the crew. I'm pretty sure I remember it singing a song like "I want to eat your face, I want to eat your..." which is why I say it was a comedy. I can't for the life of me remember the title and it has been ages since I saw it. Can anyone help?!?