Double underhook backbreaker is a type of Backbreaker.
Description[]
An attacking wrestler stands facing a bent over opponent and hooks his/her arms before then lifts the opponent as for a Tiger Driver. However, as the opponents drops back down the wrestler raises a knee and brings the opponent back down horizontally so his/her back collides with the knee of the attacking wrestler. It has been used extensively by Chris Jericho and by CM Punk (who named it the Welcome to Chicago, Motherf***er).