Mxyleprechauns! is the introductory mission for the 2011 St. Patrick's Day event, Mxyzptlk's Mischief. It can found within a character's journal upon logging into the game during the event, and can only be completed while the event is active.
Mister Mxyzptlk, an imp from the 5th-dimension, is known for the pranks he's played on Superman, Lex Luthor, and other super-powered beings over the years. Now he's learned of the mythical leprechaun, and has decided to breath new lifr into this legend. He can be found in the JLA Watchtower, where he can watch any chaos his mischief may cause.
"Oracle would like you to see what Mister Mxyzptlk requires to leave the Watchtower."
- 25 Cash