A Whacka Bump is an item found in Paper Mario, Paper Mario: The Thousand-Year Door, and Super Paper Mario.
Paper Mario[]
Whacka Bumps are obtained by hitting a Whacka. It recovers 25 HP & 25 FP. Only eight of these can be gotten before the Whacka disappears. Having Tayce T. cook one will result in a Yummy Meal, while cooking one with a Strange Leaf will result in a Deluxe Feast.
Paper Mario: The Thousand-Year Door[]
Whacka Bumps also appear in Paper Mario: The Thousand-Year Door, where they are obtained by whacking the Whacka on Keelhaul Key. Once again, eight hits make the Whacka disappear for the rest of the game. Having Zess T. cook one will result in a Zess Special, while cooking it with a Golden Leaf results in a Zess Deluxe.
A red Whacka Bump.
In the Nintendo Switch remake, the Whacka in the Pit of 100 Trials will produce a Whacka Bump every time he is hit. Whacka can use these bumps to attack Mario, dealing 10 damage, or eat a bump to recover 25 HP. There is also a stronger red variant of the Whacka Bump that can spawn during the battle, which can deal 27 damage, or heal 75 HP if Whacka decides to eat it. Defeating Whacka for the first time will reward the player with a Gold Whacka Bump, an inedible key item, while subsequent defeats will yield additional Whacka Bumps.
Super Paper Mario[]
In Super Paper Mario, the Whacka Bump heals 30 HP and cures poison. They can be purchased at the Flipside Arcade for 300 Flipside Tokens. A Whacka can be found in Chapter 5-1 at the far right wall. Mario must use Dottie to shrink and then flip to 3D. The Whacka is found in the hole. If a Whacka Bump is cooked, it creates a Roast Whacka Bump.
You can also get it from Flimm when he has it in supply.