Manaphy (マナフィ, Manafi) is a fictional creature from the Pokémon franchise.
When Manaphy appears from its Poké Ball it uses Heart Swap, its signature move, temporarily swapping the bodies of 2 players. This can be dodged via air dodge. During the heart swap, the players keep their own damage and stocks, and self-destruction causes the player to lose a stock, not the opponent. The only thing that is kept with the body is the ownership of Poké Ball Pokémon and characters from Assist Trophies.
Two players need to be close to Manaphy in order for the Heart Swap to take effect.
The Permanent Heart Swap glitch causes the effects of Manaphy's Heart Swap to last for the entirety of the player's stock. If a player under the effects of Heart Swap is KO'd and has no stock remaining, the player they switched characters with will be forced to remain as that character. Once the second player is KO'd, they will reappear as their original character.
 Trophy description
A Seafaring Pokémon. Eighty percent of its body is made of water. It has the ability Hydration, which allows it to heal status effects at the end of a turn if it's raining. It is the only Pokémon that can use the stat-effect-swapping move called Heart Swap. Place a Manaphy and a Ditto in a Pokémon Day Care, and they will produce an Egg that contains a Phione.