Blue Apple

From the Super Mario Wiki

A Blue Apple is an item in Super Paper Mario. Found on a tree in Overthere Stair, it restores five HP and cures poison. Mario and Co. thought this might have been the taboo fruit to wake up Princess Peach. But when they fed one to her, it caused her to become small, as if Dottie shrunk her. The effect wore off immediately, and Peach was still asleep, as if nothing happened.

Fruits

Apple | Banana | Bean Fruit | Berry | Black Apple | Blue Apple | Blue Banana | Blue Berry | Blue Watermelon | Bubble Berry | Cherry | Coconut | Crystal Berry | Dried Fruit | Durian | Giant Banana | Golden Apple | Grape | Green Banana | Heart Fruit | Keel Mango | Lemon | Lime | Mella Yella | Melon | Papaya | Peach | Peachy Peach | Pineapple | Pink Apple | Primordial Fruit | Red Apple | Red Berry | Red Watermelon | Star Fruit | Strawberry | Watermelon | Yellow Apple | Yellow Berry