Paper Mario/Chapter 6: Dark Days in Flower Fields

Magic Seed Mania
If you have not done so already, you must collect all four magical seeds for Mihn T.
 * Seed locations
 * Across from the pipe that leads to the sewers in Toad Town
 * Along the path before Dry Dry Desert
 * In the center of the 3rd map while making your way to Boo's Mansion
 * Give the Volcano Vase to Kolorado after beating chapter 5

Battle in the Sky
You'll encounter Huff N. Puff. Whenever you inflict damage on him, he sheds Tuff Puffs. He can inhale the Tuff Puffs to restore any damage you deal to him. Basically, have Mario attack him with a strong attack, and then have Lakilester use Spiny Surge on him, which will destroy the Tuff Puffs. Either way, this will be a tough fight, so be prepared.