Wario Land 4/Aerodent

Aerodent is one of the easiest bosses to beat. All you have to do is jump on that spike on a parachute and pick it up, throw it at the patch on Aerodent's rump, smash into Aerodent then smash the mouse. Note that if you use an item to lower Aerodent's health, it will throw fire at the ground, so avoid that.