Instructions
Run out of the way when Pete shoots thinner at you. When the thinner hits the floor you're standing on, the floor panel will evaporate. If you fall through the hole, you'll take some damage. Use your paint to rebuild the panel.
Jump up when Pete swings his sword to avoid getting hit. If Pete directs the blade at you, shake the Wii remote to do a spin attack and reflect it back at him. Pete will drop the blade and the floor around him materializes.
Run behind Pete while he's stunned and blast his back with paint or thinner until he recovers.
Go back to the outer floor panels before the floor you're standing on disappears.
Continue deflecting Pete's blades back at him, and then shoot him with paint or thinner until he's defeated.