Ellen DeGeneres [1] loves to surprise guests on her show — remember when she scared Eric Stonestreet [2] despite his best efforts to prevent it? — and Jake Gyllenhaal [3] was the latest victim of her pranks during an appearance on Tuesday. Jake and Ellen were chatting about the dark roles that he's been choosing lately, when a costumed man appeared out of nowhere, causing Jake to proclaim, "What the f*ck?!" Be warned: you might jump too when you watch, and if you can't get enough, check out more viral videos [4].