Double Jump is an ability that some characters possess. It is basically when you jump, and can jump again in midair.The double jump ability allows characters to jump and reach higher areas. Just simply press the B button twice. Mostly females double jump, but Mad Hatter and Clayface also double jump.
In the Nintendo DS version, the characters with double jump include Batman, Riddler, The Joker, Catwoman, Bruce Wayne and Selina Kyle.
Characters that can double jump: