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

A Tip from the Sun
The sun is located Left-Top of the save Poimt. Once you get to the sun he will tell you that the Huff N' Puff machine is somewhere to the east. You need to get to him for your next companion encounter.

Spike appears
On your way back from the sun you will run until Spike, spike is a simple encounter that leads to you getting your companion. He stays in the air, so use anti-air like Parakarry and make sure you use power jump, power Bounce or Hammer Throw. After defeating him he will join your party.

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.