Bouncy Wario

Bouncy Wario is one of Wario's famous transformations in the Wario Land series of games. If hit by the hammer of an Ape, Hammer-bot, or Menhammer, Wario will be squashed, only to spring right back up again in this state, used to spring to new heights. In all three versions, Wario has a time limit before he will return to normal (hitting a spike will also work). However, in Wario Land II and 3, pressing will let Wario jump slightly higher, while in Wario Land 4, pressing  will cause Wario to jump up until he hits an obstacle, allowing him to return to normal.

Trivia

 * In Super Mario Galaxy and its sequel, Mario can use a similar form: Spring Mario.
 * The way Wario looks in Bouncy form is similar to the way he looks after eating a Springo Candy in Mario Party 8.