Shell dash

A Shell Dash is a move which Mario and Luigi can perform in New Super Mario Bros. They can only do it if they are in their shell form after collecting a Blue Shell. It can be performed by running for about two seconds. After doing so, Mario or Luigi will duck into their shell and dash as if a Koopa Troopa's shell has been kicked. In this form, Mario or Luigi can jump, break Brick Blocks and defeat enemies. Unlike kicking a Koopa Troopa's shell and hitting multiple enemies to earn points and an extra life, Mario or Luigi only earn 200 points for every enemy defeated when using a Shell Dash.

There is a similar move in Super Mario 3D World. If Mario (or Luigi, Princess Peach, or Toad) holds a shell, once he dashes, he ducks into his shell and dashes. He can steer the shell slightly. He can exit the shell any time; if he does so, he does a spin jump. If he hits any team members, they downgrade or get defeated, depending on their form. After a while, Mario automatically escapes the shell, becoming dazed and stunned for a few seconds.