Brad Pitt
Brad Pitt made a split-second appearance in Deadpool 2 when he played a superhero named the Vanisher. As you might have deduced from the name, his superpower is invisibility. At least, it was until he got electrocuted and his face was revealed. Initially, Brad wanted the role of Cable, the main antagonist in the movie, but he had to back down due to scheduling conflicts. All the same, viewers were more than happy to see the actor when he made the brief appearance.