Pokémon Form Change

As the Pokémon games have progressed, many Pokémon have gained forms and in doing so, they need you to get a special item or go to a special location in order to be able to change the form which has changed from previous games. These list the ways to get specific Pokémon forms for the small amount of Pokémon with alternate forms within the games that slightly differ from normal or require specific locations

Rotom

Rotom's forms make a return once again. Once you catch Rotom in the Old Chateau, you will receive the Secret Key. Much like in Pokémon Platinum, you use this key to access a special room in the entrance of the Eterna Galactic Building. In there, you will spot various appliances, as well as notebooks that give you access to Rotom's history. When you enter the first appliance, you will receive the Rotom Catalog item which lets you change Rotom's forms wherever you are. You need to have Rotom possess each appliance to get it added to the catalogue

Rotom Mow Frost Heat Fan Wash
Rotom Mow Rotom Frost Rotom Heat Rotom Fan Rotom Wash Rotom
  Leaf Storm Blizzard Overheat Air Slash Hydro Pump
Base Stats:

HP: 50
Attack: 50
Defense: 77
Sp. Attack: 95
Sp. Defense: 77
Speed: 91
Base Stats:

HP: 50
Attack: 65
Defense: 107
Sp. Attack: 105
Sp. Defense: 107
Speed: 86
Rotom Room

Deoxys

Although Deoxys isn't available natively in the game without event or transfer, its form change method is available for when you have one. If you take it to the various meteorites in the south east of Veilstone City , you can have it change form

Top Meteorite - Speed Forme
Middle Meteorite - Normal Forme
Bottom Left Meteorite - Attack Forme
Bottom Right Meteorite - Defense Forme

Normal Forme Attack Forme Defense Forme Speed Forme
Normal Forme Attack Forme Defense Forme Speed Forme
Base Stats:

HP: 50
Attack: 150
Defense: 50
Sp. Attack: 150
Sp. Defense: 50
Speed: 150
Base Stats:

HP: 50
Attack: 180
Defense: 20
Sp. Attack: 180
Sp. Defense: 20
Speed: 150
Base Stats:

HP: 50
Attack: 70
Defense: 160
Sp. Attack: 70
Sp. Defense: 160
Speed: 90
Base Stats:

HP: 50
Attack: 95
Defense: 90
Sp. Attack: 95
Sp. Defense: 90
Speed: 180


Deoxys Meteorites

Shaymin

Although Shaymin isn't available natively in the game without event or transfer, its form change method is available for when you have one. Just like in Pokémon Platinum, there is a woman in Floaroma Town who wants to asee a Shaymin. If she sees one, she will give you the Gracidea which lets you change Shaymin's form to Sky Forme. This reverts after 7:59pm and if it gets frozen

Land Forme Sky Forme
Land Forme Sky Forme
Grass GrassFlying
Ability:
Natural Cure
Ability:
Serene Grace
Base Stats:

HP: 100
Attack: 100
Defense: 100
Sp. Attack: 100
Sp. Defense: 100
Speed: 100
Base Stats:

HP: 100
Attack: 103
Defense: 75
Sp. Attack: 120
Sp. Defense: 75
Speed: 127


Gracidea Location