Wish orbs are mystical wish-granting items that appear in "The Limit," when Finn and Jake reach the center of the Labyrinth. The orbs are guarded by Aquandrius and will grant only a single wish. Once a wish has been made, it cannot be undone. The Ancient Psychic Tandem War Elephant uses one of the orbs, while it came from one of them itself.
Throughout the series, when characters wish for things, those wishes are shown in orange balls like wish orbs (e.g. in "Ricardio the Heart Guy" Finn's wish for Princess Bubblegum to kiss him is shown this way).
Wish orbs are shown to be floating orange balls with a darker orange aura around it. The middle is made up of many small dark- and light-orange spheres, together looking like the nucleus of an atom. They somewhat resemble a gathering of eel eggs.