Head Shake

The Head Shake is an ability in Super Mario Galaxy 2. Its name comes from a term referring to a gesture used to indicate denial, disbelief, or rejection. It is effectively Yoshi's version of Mario's (or Luigi's) spin, in that it is used instead whenever he is being ridden, and has many of the same effects—it breaks crystals, activates objects, flips Red-Blue Panels, and reflects physical projectiles. However, using it to gain height in midair prevents Yoshi from flutter-jumping, and using a Flutter Jump stops the move from gaining height, meaning the two techniques cannot be combined for large jumps. The move also does not hit behind Yoshi, unlike Mario's spin, which hits on all sides.

While the move is new in Super Mario Galaxy 2 as a named technique, Yoshi's using his head as a weapon is a mainstay of previous games; he headbutts enemies in the earlier Mario Party games instead of punching, and several of his attacks in the Super Smash Bros. series are headbutts (with many of them rendering his head temporarily intangible).