7. Vanilla Ice - Teenage Mutant Ninja Turtles II: The Secret of the Ooze
Sure, crass cameos from musicians who are on a film's soundtrack is nary a new thing; it's been around for decades, but Vanilla Ice's turn in the second Turtles film really is something else altogether. Not merely limited to a quick pass through a scene or him performing his song, the Turtles end up at one of his shows, and a fight breaks out, but Ice, not wanting to disappoint his fans, spontaneously busts out a tune - singing the film's title-song, "Ninja Rap" - as they clean house. At the time - when the costumes looked awesome, and people actually liked Vanilla Ice - this was a dream come true, but in retrospect, it looks interminably dated. The only thing saving the scene is Shredder, who interrupts all the mincing around on stage just as it begins to get unbearable.