Notes on Generation IV Evolutions
Burmy, Wormadam and Mothim
Burmy evolves into Wormadam or Mothim randomly.
When Mothim's evolution is reverted, its original form is retained.
A Mothim whose evolution has been reverted is a Burmy, and as such, it evolves into Wormadam or Mothim randomly.
Combee and Vespiquen
All Combee can evolve into Vespiquen.
Budew and Roserade
A Roselia caught before Generation IV was released cannot evolve into Roserade, and its evolution cannot be reverted to Budew.
Cherubi and Cherrim
The form of Cherrim in which Cherubi can evolve is fixed and displayed as its form, in a similar manner to Alolan Pokémon.
Ambipom
An Aipom caught before Generation IV was released cannot evolve into Ambipom.
Mismagius
A Misdreavus caught before Generation IV was released cannot evolve into Mismagius.
Honchkrow
A Murkrow caught before Generation IV was released cannot evolve into Honchkrow.
Chingling
A Chimecho caught before Generation IV was released cannot have its evolution reverted to Chingling.
Bonsly
A Sudowoodo caught before Generation IV was released cannot have its evolution reverted to Bonsly.
Mime Jr.
A Mr. Mime caught before Generation IV was released cannot have its evolution reverted to Mime Jr..
Happiny
A Chansey caught before Generation IV was released cannot have its evolution reverted to Happiny.
Munchlax
A Snorlax caught before Generation IV was released cannot have its evolution reverted to Munchlax.
Mantyke
A Mantine caught before Generation IV was released cannot have its evolution reverted to Mantyke.
Weavile
A Sneasel caught before Generation IV was released cannot evolve into Weavile.
Magnezone
A Magneton caught before Generation IV was released cannot evolve into Magnezone.
Lickilicky
A Lickitung caught before Generation IV was released cannot evolve into Lickilicky.
Rhyperior
A Rhydon caught before Generation IV was released cannot evolve into Rhyperior.
Tangrowth
A Tangela caught before Generation IV was released cannot evolve into Tangrowth.
Electivire
An Electabuzz caught before Generation IV was released cannot evolve into Electivire.
Magmortar
A Magmar caught before Generation IV was released cannot evolve into Magmortar.
Togekiss
A Togetic caught before Generation IV was released cannot evolve into Togekiss.
Yanmega
A Yanma caught before Generation IV was released cannot evolve into Yanmega.
Leafeon and Glaceon
An Eevee caught before Generation IV was released cannot evolve into Leafeon nor Glaceon.
Gliscor
A Gligar caught before Generation IV was released cannot evolve into Gliscor.
Mamoswine
A Piloswine caught before Generation IV was released cannot evolve into Mamoswine.
Porygon-Z
A Porygon2 caught before Generation IV was released cannot evolve into Porygon-Z.
The game will not allow you to revert a Porygon-Z's evolution to a Porygon by using two Everstones in a row. If you wish to do so, make sure you have two Everstones, then open a support ticket, showing proof that your Porygon evolved into Porygon2 through trading, then into Porygon-Z in the same manner. Your Porygon-Z's evolution will then be reverted manually to Porygon, in exchange for the two Everstones.
Gallade
A Kirlia caught before Generation IV was released cannot evolve into Gallade.
Any Kirlia can evolve into both Gardevoir or Gallade, only depending on the item you expose it to.
Probopass
A Nosepass caught before Generation IV was released cannot evolve into Probopass.
Dusknoir
A Dusclops caught before Generation IV was released cannot evolve into Dusknoir.
Froslass
A Snorunt caught before Generation IV was released cannot evolve into Froslass.
Any Snorunt can evolve into both Glalie or Froslass, only depending on the item you expose it to.
Phione and Manaphy
Phione cannot evolve into Manaphy.
It is not planned to allow Manaphy's evolution to be reverted to Phione.