The Double Jump is a special move from Jazz Jackrabbit 2 useable only by Spaz, performed by pressing the jump button in midair. When used, Spaz performs a second jump that sends him about a tile and a half higher into the air. The double jump is considered by most players to be much more useful than both of Jazz’s special moves (helicopter ears and uppercut) mainly because it allows Spaz to change his direction instantly in midair, which is useful in dodging bullets, missiles and obstacles. When performed after a running jump, it allows him to jump much higher than Jazz could ever do with his uppercut.
The double jump manuever is also integral to a bug known as wallclimbing.
Eat your lima beans, Johnny.