Yaburu Muda (破る無駄)
Literally "to break pointlessly", the Yaburu Muda is an event at gaming conventions said to be impossible to beat. It's said to be cruel and unfair, but a rite of passage for players who want to test their mettle. Originally mentioned in D&D Aangvanced.
To enter the Yaburu Muda, players must wager with collateral of sentimental value (eg, a rare comic printing). Upon defeat, the item is destroyed in a hazing ritual. There are said to be three players who have beaten it: Shelby Brady, Sam Torres, and Micah.