may or may not qualify, because it is a name-only sequel, but it at least deserves an honorable mention.
Although it is sold with the original Troll (which was an OK but unremarkable b-movie that had some minor success) as a two-for-one DVD (which I bought), this movie
- was not made with knowledge of anyone who worked on the original Troll.
- did not feature any trolls.
- did feature goblins. The major "plot twist" in this movie is that the name of the town where they're staying, Nilbog - which incidentally is repeatedly misspelled on the back of the UK video rental box as Nilborg - is just goblin spelled backwards!.
- has special effects consisting of a rubber sheet partially covering a hole in the ground covered in green mush to show that people are being turned into vegetables (see below), because apparently goblins are herbivores (the director and his wife got the idea for the movie when several of their friends became vegetarians).
- has some of the worst acting I have ever seen in my life, and I have seen several thousand movies, and went through an extensive "I like bad movies" phase.
- was written by the director and his wife, who only spoke Italian and a minor bit of pidgin English (the costume designer was the only one of the crew who spoke fluent English and translated for the actors). As such it was written in very poor English. When the actors suggested they improvised a bit to make it sound better, he insisted the lines were spoken as written.
- features at least one actor who at the time was mentally ill, and claims he wasn't actually acting, but was rather high as a kite on MJ.
- was sold on VHS featuring a cover on which a boy with a troll doll was being chased by a werewolf, with neither doll nor lycanthrope appearing in the actual film.
- more here