Devolution

Slowbro losing Shellder

Devolution (Japanese: 退(たい)() degeneration) is the process by which an evolved Pokémon reverts to its previous form. This process is much less common than Evolution due to being impossible within the core series games. In most media in which it exists, devolution is often instigated through artificial means, such as sprays or genetic engineering.

In the core series games

Slowking losing Shellder

While devolution is not possible within the core series games as a mechanic, the notion is referred to by Slowbro's numerous Pokédex entries. Said entries claim that if the Shellder falls off, the Slowbro turns back into a Slowpoke. It is said that if Slowking loses its Shellder, it forgets everything it has learned.[1]

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

Silvally, a Pokémon who had previously gone by the name Type: Full were given control helmets to prevent its RKS System from functioning. This had caused the Pokémon to be renamed to Type: Null, essentially devolving it into an inferior species. Type: Null, both in lore and gameplay, can evolve back into Silvally.

In Melmetal's Pokédex entry for Pokémon Sword, it is stated that, at the end of a Melmetal's lifespan, its leftover shards will return to being Meltan.

In the spin-off games

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.

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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.

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Pokémon Trading Card Game

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

Pokémon UNITE

Before a Unite Battle, all participating Pokémon are reduced to level 1 through the power of Aeos energy.[2] This seemingly also induces devolution in the affected species, however the process is not seen within the bounds of the video game. Pokémon with baby forms, such as Pikachu and Mr. Mime, are never seen in such stages and presumably do not devolve that far, while Azumarill only devolves to Marill.

The opening cinematic for Pokémon UNITE shows Talonflame, Slowbro, Greninja, Cinderace, and Garchomp enveloped by a blue aura and devolving into their base forms of Fletchling, Slowpoke, Froakie, Scorbunny, and Gible, respectively. Notably, Pikachu, Mr. Mime, Absol, Lucario and Snorlax are seen enveloped in the same blue aura but are unaffected.

In the Practice Area mode, if the player uses the Reset Level function in the Practice Options menu to return a Pokémon to Level 1, that Pokémon will devolve back into their base form. Just like Evolution, Pokémon are invincible while devolving. The same visual effects from Evolution indicate devolution.

In animation

Wobbuffet devolving in Pokémon Journeys: The Series

Pokémon the Series

In Pokémon the Series, the subject of devolution has rarely been brought up. Brock explicitly states in Electric Shock Showdown that Evolution cannot be reversed, effectively confirming the nonexistence of devolution within the series. This was reconfirmed in A Stealthy Challenge!, where Bonnie asked Frogadier to devolve into Froakie so she could see it evolve again, but Clemont explained that it doesn't work that way. However, special circumstances have caused some Pokémon to devolve in the series.

Pokémon the Series: XY

In Dream a Little Dream from Me!, Ash's Pikachu had a nightmare featuring Frogadier having devolved into Froakie. Clemont's Bunnelby, which appeared as a Diggersby in the same nightmare, also devolved back into its first stage later in the dream.

Pokémon the Series: Sun & Moon

The first known instance of a real devolution in the series occurred when Faba fitted Silvally with a restraining mask, thereby turning it into a Type: Null.

Pokémon Journeys: The Series

In The Gates of Warp!, Pokémon in an alternate world version of Sinnoh devolved due to Dialga and Palkia's battle, with most of them eventually reverting all the way into Eggs. In Showdown at the Gates of Warp!, this battle was revealed to have been orchestrated by Alternate World Team Rocket to make Pokémon easier to steal and train to serve them. Once they had been defeated, Ash, Dawn, Goh, Chloe, and their alternate world counterparts prayed for Arceus to stop the fight, which it did. Afterwards, Dialga and Palkia restored the reverted Pokémon to normal, fulfilling everyone's wish.

In the manga

Eevee devolving from Jolteon in Pokémon Adventures

Pokémon Adventures

Red, Green & Blue arc

Before Vee, Red's Eevee, evolved into Espeon, 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.

Pokémon Pocket Monsters

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 Pikachu evolve into Clefable and Raichu respectively, then revert to their original forms, as well as when Green's Charmander evolved into Charizard and then turned back into Charmander.

Pokémon Horizon

Akira's Rockruff has the unique ability to evolve into Lycanroc and then devolve into Rockruff again, thanks to the strange red stone on its neck. It also has the ability to change in between its Midday and Midnight Forms while being evolved.

In the TCG

Devolution Spray, an example of a card that can induce devolution in the TCG

In the TCG, devolution is possible, albeit only through effects rather than as a rule of the game. Examples include Mew's Devolution Beam attack, Flareon's Undevelop Poké-Power, and the Devolution Spray Item card.

Devolution is performed by removing one or more of the Evolution cards on top of the Pokémon and moving them to another zone. Typically, the cards return to their owner's hand. This leaves one of the lower stages of that Pokémon visible, and that prior card is now in play. Devolution is only possible for Pokémon that have already evolved, meaning they are an evolved Pokémon. This is not to be confused with an Evolution Pokémon, which is just a Pokémon card that has a Stage which is not Basic, Restored, Baby, LEGEND, or V-UNION. For example, if Frogadier from BREAKpoint uses its Water Duplicates attack to put other Frogadier onto the Bench, the other Frogadier cannot be devolved because they are unevolved Pokémon and therefore do not have previous Evolutions. It should also be noted that a Pokémon cannot be devolved past whichever card was put into play without Evolution. That card will remain in play no matter what effect is trying to devolve the Pokémon, even if that card happens to be an Evolution card.[3] To continue the example, if any of the unevolved Frogadier evolve into Greninja, then they are evolved Pokémon and can be devolved. However, an effect that attempts to remove multiple Evolution cards like Shining Jirachi's Stellar Reign attack would only remove the Greninja; Frogadier would stay in play.

Devolving a Pokémon LV.X has a strange effect, as a Pokémon LV.X is not an Evolution card. This means one can only devolve a Pokémon LV.X that is an evolved Pokémon. If so, then the Evolution card below the LV.X card is removed. In most cases, this means that the Pokémon LV.X is now a Level-Up of a card it does not Level-Up from. This causes the LV.X card to be removed from play, leaving the prior Evolution in place. The rulebook is unclear about where the LV.X card goes after that.[4]

A Pokémon that devolved cannot evolve on the same turn, unless some other effect allows it to evolve in spite of this.

One of the primary purposes of devolution is reducing the maximum HP of a Pokémon, as HP usually increases as a Pokémon evolves. If, after devolving, a Pokémon has more damage counters on it than its current maximum HP, it is Knocked Out. Another use case is reusing effects, such as Abilities, that activate when a Pokémon evolves, although reusing effects in this manner is usually restricted to happening over two turns due to the Evolution rules unless there is a second Pokémon in play that can evolve into the Pokémon card that was removed from the first Pokémon.

The following is a list of cards that can induce devolution.

Pokémon cards

Pokémon cards that devolve user's own Pokémon

Pokémon cards that devolve user's own Pokémon
Cards listed with a blue background are only legal to use in the current Expanded format.
Cards listed with a green background are legal to use in both the current Standard and Expanded formats.
Card Type Mark English
Expansion
Rarity # Japanese
Expansion
Rarity #
Mew Psychic Wizards Black Star Promos   8 Unnumbered Promotional cards   8
Wizards Black Star Promos   9 Mystery of the Fossils Rare Holo  
Unown Psychic EX Unseen Forces D/28 Golden Sky, Silvery Ocean Uncommon 046/106
Mew Psychic Nintendo Black Star Promos   040 PCG-P Promotional cards   080/PCG-P
        PCG-P Promotional cards   085/PCG-P
Ninetales δ Psychic EX Dragon Frontiers 8/101 Offense and Defense of the Furthest Ends Rare Holo 030/068
Flareon Fire Rising Rivals 19/111 Bonds to the End of Time Rare 011/090
Jolteon Lightning Rising Rivals 26/111 Bonds to the End of Time Rare 028/090
Vaporeon Water Rising Rivals 34/111 Bonds to the End of Time Rare 014/090
Porygon-Z Colorless Ancient Origins 67/98 Bandit Ring R 067/081
Celebi Prism Star Grass B Lost Thunder 19/214 Super-Burst Impact PR 015/095
 

Pokémon cards that devolve opponent's Pokémon

Pokémon cards that devolve opponent's Pokémon
Cards listed with a blue background are only legal to use in the current Expanded format.
Cards listed with a green background are legal to use in both the current Standard and Expanded formats.
Card Type Mark English
Expansion
Rarity # Japanese
Expansion
Rarity #
Mew Psychic Wizards Black Star Promos   8 Unnumbered Promotional cards   8
Wizards Black Star Promos   9 Mystery of the Fossils Rare Holo  
Dark Omastar Water Neo Destiny 19/105 Darkness, and to Light... Rare  
Mew ex Psychic         PLAY Promotional cards   007/PLAY
Omastar Water EX Sandstorm 19/100 Magma VS Aqua: Two Ambitions Rare Holo 024/080
EX Power Keepers 20/108 World Champions Pack Rare 017/108
Lileep Grass EX Sandstorm 42/100 Miracle of the Desert Uncommon 009/053
Espeon ex Psychic EX Unseen Forces 102/115 Golden Sky, Silvery Ocean Rare Holo ex 041/106
Unown Psychic EX Unseen Forces D/28 Golden Sky, Silvery Ocean Uncommon 046/106
Cradily Grass EX Legend Maker 3/92 Mirage Forest Rare Holo 014/086
Haunter Psychic EX Legend Maker 35/92 Mirage Forest Uncommon 039/086
Mew ex Psychic EX Holon Phantoms 100/110 Mew Quarter Deck   003/015
Mew Psychic Nintendo Black Star Promos   040 PCG-P Promotional cards   080/PCG-P
        PCG-P Promotional cards   085/PCG-P
Dialga Metal Diamond & Pearl 1/130 Space-Time Creation Rare Holo  
Great Encounters 16/106 Dialga LV.X Constructed Standard Deck    
        DP-P Promotional cards   033/DP-P
DP Black Star Promos   DP26 DP-P Promotional cards   042/DP-P
Shiftry Darkness Diamond & Pearl 14/130 Space-Time Creation Rare Holo  
Omastar Water Majestic Dawn 26/100 Moonlit Pursuit Rare  
Omastar Water Arceus 23/99 Advent of Arceus Rare 023/090
Jirachi Psychic Unleashed 1/95 Metagross Deck   006/014
Call of Legends 11/95        
Golurk Psychic Dragons Exalted 59/124 Dragon Blade R 023/050
Boundaries Crossed 150/149 Freeze Bolt UR 064/059
Claydol Psychic Ancient Origins 33/98 Bandit Ring U 033/081
EspeonEX Psychic BREAKpoint 52/122 Rage of the Broken Heavens RR 035/080
BREAKpoint 117/122 Rage of the Broken Heavens SR 084/080
        The Best of XY   045/171
Porygon-Z Colorless A Burning Shadows 105/147 Darkness that Consumes Light R 044/051
Yellow A Alternate cards   105a/147 SM-P Promotional cards   070/SM-P
Shining Jirachi Psychic A Shining Legends 42/73 Shining Legends Shining Holo 043/072
Dialga Metal B Lost Thunder 127/214 Thunderclap Spark R 038/060
Celebi Grass C Unified Minds 4/236 Miracle Twin R 003/094
Banette Psychic D Vivid Voltage 068/185 Legendary Heartbeat U 027/076
GolurkV Psychic E Evolving Skies 070/203 Skyscraping Perfection RR 015/067
Evolving Skies 181/203 Skyscraping Perfection SR 069/067
Evolving Skies 182/203 Skyscraping Perfection SR 070/067
        Start Deck 100   188/414
Porygon-Z Colorless F Lost Origin 142/196 Lost Abyss U 085/100
Aerodactyl Colorless G 151 142/165 Pokémon Card 151 R 142/165
Espathra Psychic H Surging Sparks 095/191 Paradise Dragona U 023/064
Espeonex Psychic H Prismatic Evolutions 034/131 Terastal Fest ex RR 063/187
Prismatic Evolutions 155/131 Terastal Fest ex SAR 211/187
Archeops Fighting I White Flare 051/086 White Flare R 048/086
White Flare 132/086 White Flare AR 130/086
 

Trainer cards

Trainer cards that devolve user's own Pokémon

Trainer cards that devolve user's own Pokémon
Cards listed with a blue background are only legal to use in the current Expanded format.
Cards listed with a green background are legal to use in both the current Standard and Expanded formats.
Card Type Mark English
Expansion
Rarity # Japanese
Expansion
Rarity #
Devolution Spray I Base Set 72/102 Expansion Pack Rare  
Dragons Exalted 113/124 Dragon Blast Uncommon 048/050
        BW-P Promotional cards   196/BW-P
Fates Collide 95/124 Awakening Psychic King U 067/078
Evolutions 76/108 Expansion Pack 20th Anniversary U 075/087
Hyper Devolution Spray T Neo Discovery 73/75 Crossing the Ruins... Uncommon  
        Pokémon Web Uncommon 031/048
Devolution Spray Z I C Unbroken Bonds 166/214 Full Metal Wall U 044/054
Suspicious Watch I I         Mega Symphonia U 057/063
 

Trainer cards that devolve opponent's Pokémon

Trainer cards that devolve opponent's Pokémon
Cards listed with a blue background are only legal to use in the current Expanded format.
Cards listed with a green background are legal to use in both the current Standard and Expanded formats.
Card Type Mark English
Expansion
Rarity # Japanese
Expansion
Rarity #
Mystery Plate γ T Skyridge 135/144 Split Earth Uncommon 085/088
Ancient Technical Machine Rock T EX Hidden Legends 85/101 Undone Seal Uncommon 076/083
Technical Machine: Devolution PT G Paradox Rift 177/182 Ancient Roar U 063/066
        Stellar Miracle Deck Build Box   029/044
        Terastal Fest ex   161/187
        Battle Partners Deck Build Box   030/045
        Premium Trainer Box MEGA   034/043
 

Energy cards

Energy cards that devolve user's own Pokémon

Energy cards that devolve user's own Pokémon
Cards listed with a blue background are only legal to use in the current Expanded format.
Cards listed with a green background are legal to use in both the current Standard and Expanded formats.
Card Type Mark English
Expansion
Rarity # Japanese
Expansion
Rarity #
Retro Energy Colorless E Skyridge 144/144 Mysterious Mountains Uncommon 088/088
 

References

Related articles

Game mechanics Evolution prevention • • Evolution move
Methods of Evolution Level-based EvolutionEvolution item (Evolution stone) • Trade EvolutionFriendship Evolution
Time-based EvolutionGender-based EvolutionMove-based Evolution
Location-based EvolutionRegion-based EvolutionGame-based Evolution
Lists of Pokémon Evolutionary line (GO) • No evolutionary lineBranchedCross-generationLevels
Methods of Evolution by index number (Gen IGen IIGen IIIGen IV • Gen V • Gen VI • Gen VII • Gen VIII • Gen IX)
In spin-off games Evolution in Mystery Dungeon (items) • Evolution in Pinball (items)
Data structures Pokémon Evolution data structure (Gen IIIGen IV)