Paopu Fruit

A Paopu Fruit is a star shaped fruit native to Destiny Islands.

Kingdom Hearts
In an early scene in Kingdom Hearts, Riku explains the fruit to Sora while on the bridge in Destiny Islands. Riku tosses him one and tells him a legend that says that if two people share the same Paopu Fruit, they will remain a part of each other's lives forever. Later on, while racing for the right to name the raft they have built, Riku raises the stakes. He says that the winner should get to share a Paopu fruit with Kairi. This intensifies the rivalry between the two, both to prove who is stronger and to gain Kairi's attention.

Kingdom Hearts: Chain of Memories
In Kingdom Hearts: Chain of Memories, the fake good luck charm Naminé gave to Sora in Castle Oblivion, also resembles a Paopu fruit.

Kingdom Hearts II
In Kingdom Hearts II, the Paopu Fruit is the keychain on Kairi's Keyblade.