A Badge is an item in the Paper Mario series. When worn, they give the wearer a certain ability. They appear in Paper Mario and Paper Mario: The Thousand-Year Door.
There are many kinds, and most require specially obtained Badge Points (BP) to wear and use. They provide a variety of benefits, ranging from fire-protection to attack power. Usually, the stronger, more expensive, rarer, etc. badges use more BP than lower ones. On the other hand, some badges do not affect Mario's stats in a beneficial way. For example, some badges create certain noises when Mario uses his hammer, while others change the color of his clothes. Also, some badges actually make it harder to win battles or do tasks, such as the Slow Go badge that slows down your running speed. All non-beneficial and harmful badges take no BP to use, as they do not help Mario or his allies in any way. .