evidence: That Time Jim Carrey Totally Mooned A Dumb And Dumber Co-Star To Help With A Key Scene [...] As the epitome of good-natured prankery, comedy legend Jim Carrey knows how to shock people. At any given moment, the man can pull a face or a pratfall that’ll break the room, with results that sometimes wind up on camera. One such example of that skill at work contributed one of the most memorable scenes in Dumb and Dumber, as Carrey mooned a co-star out of nowhere to help with his performance. [...] At that point in his career, Carrey was a pretty big deal. Already a rising star from his time on In Living Color, the Canadian actor would score one of the ultimate hat tricks in 1994. With Ace Ventura: Pet Detective, The Mask and Dumb and Dumber all landing in the same year, that particular run yielded some of the reasons why Jim Carrey is the most important actor. But even in the middle of it all, it was enough to intimidate Cam Neely a little bit.