Instructions
Wait for the hopper to approach Mickey. Don't let the hopper get too close, or he will push you off of a cliff.
Point the Wii remote at the hopper and press the "Z" button located on the nunchuck to release a burst of thinner. Hit the hopper with thinner until it stops moving.
Shake the Wii remote to use Mickey's spin move to destroy the stunned hopper, then move past it and continue your quest.