The clip you've likely seen:
Why you should watch the rest: This is a great terrible movie. Very little sense is made through the whole movie, mostly because the director (who only spoke Italian) chose a cast of people who had never acted in their lives, but also because the story is ridiculous.
What you should know before you watch: This movie has nothing what so ever to do with the first Troll movie (which is another Michael Moriarty gem), titling it Troll 2 was an afterthought by producers. This is a stand alone movie about vegetarian goblins trying to turn a family into vegetables.
What you should watch after: Best Worst Movie natch! It's a great documentary on the bad movie resurgence. It illustrates how loving people are when it comes to bad movies and what kind of toll a resurgence can take on the people involved.
Best Worst Movie: Often cited as the “best worst film”, we sort of disagree. We feel Troll 2 is more of a gateway bad movie; you get a taste of the fringe world of cinema, but there's so much more out there!