Serebii

Fleeing a relentless Pokémon Hunter, this legendary forest guardian accidentally teleported through time, landing in the era of Ash Ketchum. After being captured by the villainous Iron-Masked Marauder via a Dark Ball, the mythical creature was rescued by Ash and his companions. Though initially unable to recover from its wounds, a massive gathering of Celebi from different eras provided the necessary healing. This time-traveling entity later appeared in Pokémon Chronicles, even whisking Ritchie into the past to save a Pokémon Center.