Zap Tap

Zap Tap is a badge in Paper Mario and Paper Mario: The Thousand-Year Door. In Paper Mario, it can be bought from Merlow for 10 Star Pieces, and in Paper Mario: The Thousand-Year Door, it is the reward for reaching the thirtieth level of the Pit of 100 Trials, found in a treasure chest. If equipped by Mario, it electrifies him, causing any enemy that makes direct contact with him to take a small amount of damage. This applies to any physical attacks that an enemy may perform (excluding contact outside of battle), though it does not apply when Mario attacks. The contact damage also ignores the enemy's defense stat. It does not affect the enemy's attack, although it will prevent Bandits from stealing anything, and Fuzzies and Swoopulas deal no damage at all. It also interrupts attacks that hit multiple times, such as from the Shy Squad or The Master. In addition, although not mentioned in-game, if Mario is electrified he can jump on an electrified enemy (mostly Dark or Ruff Puffs and Huff N. Puff) without taking damage.

Merluvlee's prediction in Paper Mario

 * "I see...a Zap Tap Badge. There is a child upstairs in the fortune-teller's house on Shooting Star Summit. Hey! I'm that fortune-teller! Anyway, the child is my brother, Merlow. He will trade Star Pieces for Badges. Head upstairs to see him!"