The Fire Pop is a recipe found in Paper Mario and Paper Mario: The Thousand-Year Door. It looks like a lollipop with a swirl in fiery colors. It can be sold for 20 coins at any store.
In Paper Mario, Tayce T. can make one by mixing a Fire Flower and a Cake Mix. It restores 20 FP, but takes away 1 HP. This is a trade-off between the attacking power of the Fire Flower, and the healing power of other Pops. Due to a bug, if Mario knocks himself out by eating a Fire Pop, then is restored by a Life Shroom, his partner is able to take an extra action.
In Paper Mario: The Thousand-Year Door, Zess T. can make a Fire Pop using the same recipe, but can also make one by substituting Hot Sauce for the Fire Flower. In this game, the Fire Pop will restore 20 FP without damaging Mario.