Paper Mario: The Thousand-Year Door Cheats

Atomic Boo and Lucky Start
NOTE: You can be in any part of the game to do this.

First, Go to the Creepy Steeple once you freed all of the boos. Go into the main hallway and stand in the middle. All of the boos will start to wrap around you. Do your Super Hammer attack to shake them off. Repeat one more time. They will get angry and form a gigantic boo. Once you are done fighting it, it will leave a badge named "Lucky Start". This badge makes something good happen before a battle.