Troll 2.
A soundtrack completely done on one old Casio keyboard. Actors (and I use the term loosely) who were chosen solely because they happened to live in the town it was shot in. The DVD cover has a picture of a werewolf chasing a boy - which has absolutely nothing to do with the movie. Despite it being a sequel, it has absolutely nothing to do with Troll 1. In fact, it doesn't even have a troll in it, just plant eating goblins that decide it's easier to turn people into plants and eat them than it is to, you know, find a plant.
So bad it spawned Troll 3, which as you can guess from the title, is about killer tree roots.
Smashing stuff.