Ground Fire

Ground Fire (グランドファイア) is X's weapon from defeating Mattrex. In normal fire, it throws a fireball on the ground that shoots embers in various directions. When charged up, it sends two fiery blasts on both sides of X. This weapon is Axle the Red's weakness. 

Trivia

 * Interestingly, the charged version of Ground Fire is similar to that of the charged version of that of Double Cyclone.