The Whirlwind is an item that appears in Spirit Tracks. It is found in the first main dungeon of the game, the Forest Temple. The whirlwind is shaped like a propeller that can shoot out gusts of wind at various enemies, spin propellers, or blow away poisonous fog. In order to use the whirlwind, the stylus must be pressed down in the proper direction, which creates a small yellow beam of light in the direction Link is facing. Once he locks on to the target, you must blow into the Nintendo DS microphone and this will sent out a gust towards whatever Link is aiming at.
The whirlwind has quite a diverse range of uses. It can be used to defeat enemies by blowing things towards them, such as spiked balls, or even other enemies. It can also be used to clear paths of purple fog that block Link's way. The whirlwind is also useful in acquiring unreachable items and solving puzzles. Link can create whirlwinds and then send them to unreachable platforms, and it may blow whatever is on the platform to an area where Link can reach. This commonly occurs when there are small keys in center platforms that Link cannot reach. Lastly, the whirlwind is used for hitting switches or turning certain objects in order to solve puzzles. Link can send whirlwinds across pits in order to hit switches on the other side, which will create a bridge for Link to cross.
This item is key to defeating the Forest Temple's boss, Stagnox, Armored Colossus.