The Flop Box is a glitch founded by a YouTuber called TaleOfTheToaster (under a different account, however) in Super Smash Bros. Brawl. Not much is known about the glitch currently, not even the founder could explicitly state how it is triggered, but it works roughly by activating a drop block, walking up a ramp, and back to where the drop block would be, at which point the player would teleport into the bottom blast line. It is currently confirmed to work with Mario, Luigi and Lucas. A demonstration of the glitch can be found here.