Geno Boost

From the Super Mario Wiki

Geno Boost is a Special Move that can Geno learn at level eight in Super Mario RPG: Legend of the Seven Stars. It increases attack power by a small amount. If timed right it will not only increase attack power but defense as well. To time it, the player must press "Y" right before the final arrow disappears. The Geno Boost uses 4 Flower Points to execute.