Spring Jump (Sonic the Hedgehog)
From the Super Mario Wiki
Spring Jump is Sonic's up special move in Super Smash Bros. Brawl and Super Smash Bros. for Nintendo 3DS / Wii U. When used, Sonic pulls a Spring from the Sonic the Hedgehog series and uses it to bounce really high in the air. He can use this both on the ground and in mid-air. If he uses it on the ground, it will stay on the ground, allowing him and other characters to bounce on it as well. Sonic cannot do damage when using the spring, however, he can still use his aerial moves (but no special moves) afterwards (one of very few up special moves that can do so). When the spring falls in midair and hits an opponent, it sends them straight downwards and deals some minor damage. Sonic can also use this move to recover from getting knocked off the edge of a stage.
In Super Smash Bros. for Nintendo 3DS / Wii U, Spring Jump has two custom variants: Double Spring and Springing Headbutt. Double Spring gives an extra spring, but reduces the jump height to compensate. Springing Headbutt allows Sonic to attack on the initial jump, but the spring disappears when it hits the ground and the jump is also slightly lower.