Thein one of the Masks in Majoras Mask which will change links form. The Deku Mask is used to turn Link into a Deku Skrub.
Discription
The first is the spin attack, although not with a sword. This is available from the moment Link is transformed into a Deku. It is useful for defeating enimies, although it may only stun others. It can also be used to cut down grass. Also, it gives link a tiny boost of speed when used while moving.
The next of these abilities is when Deku Link buries himself into certain flowers found in the floor. Once released he will shoot out and, if aimed right, can be used to defeat enimies. If left inside for several seconds longer, until smoke comes out of the flower, he will be holding 2 pink flowers, which will give him the ability to hover for a limited amount of time. This it useful for getting across some seemingly impossible gaps.
The third is the bubble blast. After recieving magic power from the great fairy in North Clock Town, the player can hold the B button, which puts you in first person mode, and see a bubble expanding. This can be used to hit close renge items and enimies, but mover slowly, so is not and extremy reliable attack.