Devolution

Devolution (Japanese: 退化 degeneration) is the process of an evolved reverting to its previous form. This is not nearly as well-known among the fandom as evolution is, due to devolution being impossible within the and. In most media in which it exists, devolution is not nearly as commonplace as evolution, and is generally brought about mainly through artificial means, such as sprays or genetic engineering.

In the games
While devolution is not possible within the core series games, the notion is referred to by 's numerous Pokédex entries. Said entries claim that if the falls off, the Slowbro turns back into a Slowpoke. It is said that if loses its Shellder, it forgets everything it has learned.

A similar situation applies to, as it is stated in its Pokédex entries that if one of its heads were to fall off, it would become an.

Pokémon Mystery Dungeon
The only Pokémon games in which devolution is possible are games from the Pokémon Mystery Dungeon series games of the Nintendo 3DS.

In Pokémon Mystery Dungeon: Gates to Infinity, the Devolve Orb is a Wonder Orb that devolves all enemies in the room.

In Pokémon Super Mystery Dungeon, the player and their partner evolve and later devolve three times during the game's main story, thanks to the Harmony Scarves they wear.

Pokémon Trading Card Game
Pokémon cards can devolve in, which contain cards that can cause devolution.

In the anime
In the Pokémon anime, the subject of devolution has rarely been brought up. explicitly states in Electric Shock Showdown that evolution cannot be reversed, effectively confirming the nonexistence of devolution within the anime. This was reconfirmed in A Stealthy Challenge!, where asked  to devolve into  so she could see it evolve again, but  explained that it doesn't work that way.

The only known instance of devolution in the anime occured when Faba put into a restraining mask thereby turning it into a.

In the Pokémon Adventures manga
Before Vee, 's, evolved into , he had been the subject of an experiment by Team Rocket, which allowed him to evolve into any of his three evolutions that were known at the time. He was also able to devolve back into an Eevee and evolve into a different Eeveelution. Although this does mean that devolution is possible in Pokémon Adventures, the artificial means through which this was achieved and the lack of any other instances of devolution suggest that it may not be possible through natural means.

In the Pokémon Pocket Monsters manga
Unlike any other media, Pokémon are capable of devolving just as easily as they evolve in Pokémon Pocket Monsters. This became especially evident when Red's Clefairy and evolve into  and  respectively, then revert to their original forms, as well as when 's  evolved into  and then turned back into Charmander.

In the TCG
In the TCG, devolution is perfectly possible, albeit not at a player's whim. Devolution must be induced by the effects of an attack, a TCG Pokémon Power (Poké-Power), or a TCG Trainer card. Examples include 's Devolution Beam attack, 's Undevelop Poké-Power, and the. Such instances are extremely uncommon. The following is a list of cards that can achieve devolution.