Mega Evolution

Blaziken, Mega Evolving into Mega Blaziken.

Mega Evolution a special kind of evolution that only affect certain kinds of Pokémon. It is discovered in Kalos, but as of right now, Mega Evolution still hold many mysteries.

Korrina and her grandfather Gherkinn (both hailing from Shalour City) are said to know a few secrets from Mega Evolving. Steven Stone, Pokémon Champion from Hoenn, is also intrigued by this process.

According to a Kalosian legend, Lucario was the very first Pokémon that ever Mega Evolved.

There's a process known as Primal Reversion, which has its similarities with Mega Evolution. Groudon and Kyogre can undergo through this to become Primal Groudon and Primal Kyogre, respectively. However, it is unknown if Rayquaza can use this process.

Usage

Key Stones usually take the appearance of this Mega Evolution sigil.

In order for a Pokémon to Mega Evolve, it first has to hold the correct Mega Stone, appropriately named after itself. A Blaziken has to Mega Evolve by holding a Blazikenite. If it's holding something like a Venusaurite, it won't work, as it only works for Venusaur. However, its Trainer has to hold and activate a Key Stone in order to have it work. The Key Stone can literally be hung or placed anywhere the Trainer wants: in a ring, bracelet, necklace, glasses, etc. But even with the necessary items in place, the Pokémon is unable to Mega Evolve if it doesn't have a strong bond with its Trainer.

A Pokémon can only Mega Evolve during a battle, and the Trainer can only Mega Evolve one Pokémon per battle. Mega Evolution is revertible, but the Mega Pokémon can only turn back into its original state when the battle is over, or when it faints. When a fainter Pokémon is revived, but already Mega Evolved before it fainted in the same battle, it cannot Mega Evolve again for the same match.

Mega Evolution can be used on the same turn as a normal attack, and always has priority before anything else.

Mega Stones cannot be stolen or switched with another item from other Pokémon. Therefor, Thief and Covet will turn into a regular attack, and the abilities Pickpocket and Magician will never succeed to take away a Mega Stone. The holder cannot get rid of a Mega Stone either, so moves like Fling and Bestow will fail instantly.

Moves that prevent the usage of held items, like Embargo or Wonder Room, do not prevent Mega Evolution. Status conditions won't prevent the Pokémon from Mega Evolving either.

There are only two instances when a Pokémon cannot Mega Evolve: shifting positions during a Triple Battle, and during the airborne phase of Sky Drop, when the target can basically do nothing at all.

Effects

Aside from the Pokémon having "Mega" before its name (e.g. Mega Scizor), they get a vast changes in their stats. The HP stat is the only stat that won't ever be affected. The stat boosts will give each Mega Evolution a boost of 100 points to their Base Stat Total. Mega Alakazam is the only exception, whose Base Stat Total boost is just 90 points.

These stat changes can completely turn a Pokémon and its strategies around. For example, Garchomp's highest stats were Attack and Speed, but its lowest were Special Attack and Special Defense, so it was typically used as a physical sweeper. However, Mega Garchomp has its Speed as its lowest stat, and gained a tremendous boost in Attack and Special Attack.

Aside from stats, the Pokémon usually gets its Ability changed as well. Sometimes, they get a different type combination. They can gain a new type while originally just single-typed (e.g. pure Electric-type Ampharos becomes Electric/Dragon), have their secondary type switched out for another (e.g. Mega Gyarados is Water/Dark, as opposed to regular Gyarados's Water/Flying), or removed altogether to become a single type (e.g. Aggron loses its Rock-type after Mega Evolution, becoming pure Steel).

The original movement order remains intact on the turn when Mega Evolution is activated, so the improvements or declines will be realized on the next turn instead.

List of Mega Evolution-capable Pokémon

Official

Before Mega Evolution				After Mega Evolution				Mega Stone
Pokémon	Type		Ability/ies	Pokémon	Type		Ability
Venusaur	Grass	Poison	Overgrow Chlorophyll (Hidden)	Mega Venusaur	Grass	Poison	Thick Fat	Venusaurite
Charizard	Fire	Flying	Blaze Solar Power (Hidden)	Mega Charizard X	Fire	Dragon	Tough Claws	Charizardite X
				Mega Charizard Y	Fire	Flying	Drought	Charizardite Y
Blastoise	Water		Torrent Rain Dish (Hidden)	Mega Blastoise	Water		Mega Launcher	Blastoisinite
Alakazam	Psychic		Synchronize Inner Focus Magic Guard (Hidden)	Mega Alakazam	Psychic		Trace	Alakazite
Slowbro	Water	Psychic	Oblivious Own Temper Regenerator (Hidden)	Mega Slowbro	Water	Psychic	Shell Armor	Slowbronite
Gengar	Ghost	Poison	Levitate	Mega Gengar	Ghost	Poison	Shadow Tag	Gengarite
Kangaskhan	Normal		Early Bird Scrappy Inner Focus (Hidden)	Mega Kangaskhan	Normal		Parental Bond	Kangaskhanite
Pinsir	Bug		Hyper Cutter Mold Breaker Moxie (Hidden)	Mega Pinsir	Bug	Flying	Aerilate	Pinsirite
Gyarados	Water	Flying	Intimidate Moxie (Hidden)	Mega Gyarados	Water	Dark	Mold Breaker	Gyaradosite
Aerodactyl	Rock	Flying	Rock Head Pressure Unnerve (Hidden)	Mega Aerodactyl	Rock	Flying	Tough Claws	Aerodactylite
Mewtwo	Psychic		Pressure Unnerve (Hidden)	Mega Mewtwo X	Psychic	Fighting	Steadfast	Mewtwonite X
				Mega Mewtwo Y	Psychic		Insomnia	Mewtwonite Y
Ampharos	Electric		Static Plus (Hidden)	Mega Ampharos	Electric	Dragon	Mold Breaker	Ampharosite
Scizor	Bug	Steel	Swarm Technician Light Metal (Hidden)	Mega Scizor	Bug	Steel	Technician	Scizorite
Heracross	Bug	Fighting	Swarm Guts Moxie (Hidden)	Mega Heracross	Bug	Fighting	Skill Link	Heracronite
Houndoom	Dark	Fire	Early Bird Flash Fire Unnerve (Hidden)	Mega Houndoom	Dark	Fire	Solar Power	Houndoominite
Tyranitar	Rock	Dark	Sand Stream Unnerve (Hidden)	Mega Tyranitar	Rock	Dark	Sand Stream	Tyranitarite
Sceptile	Grass		Overgrow Unburden (Hidden)	Mega Sceptile	Grass	Dragon	Lightning Rod	Sceptilite
Blaziken	Fire	Fighting	Blaze Speed Boost (Hidden)	Mega Blaziken	Fire	Fighting	Speed Boost	Blazikenite
Swampert	Water	Ground	Torrent Rain Dish (Hidden)	Mega Swampert	Water	Ground	Swift Swim	Swampertinite
Gardevoir	Psychic	Fairy	Synchronize Trace Telepathy (Hidden)	Mega Gardevoir	Psychic	Fairy	Pixilate	Gardevoirite
Sableye	Dark	Ghost	Stall Keen Eye Prankster (Hidden)	Mega Sableye	Dark	Ghost	Magic Bounce	Sablinite
Mawile	Steel	Fairy	Intimidate Hyper Cutter Sheer Force (Hidden)	Mega Mawile	Steel	Fairy	Huge Power	Mawilite
Aggron	Steel	Rock	Sturdy Rock Head Heavy Metal (Hidden)	Mega Aggron	Steel		Filter	Aggronite
Medicham	Fighting	Psychic	Pure Power Telepathy (Hidden)	Mega Medicham	Fighting	Psychic	Pure Power	Medichamite
Manectric	Electric		Static Lightning Rod Minus (Hidden)	Mega Manectric	Electric		Intimidate	Manectite
Altaria	Dragon	Flying	Natural Cure Cloud Nine (Hidden)	Mega Altaria	Dragon	Fairy	Pixilate	Altarite
Banette	Ghost		Insomnia Frisk Cursed Body (Hidden)	Mega Banette	Ghost		Prankster	Banettite
Absol	Dark		Pressure Super Luck Justified (Hidden)	Mega Absol	Dark		Magic Bounce	Absolite
Salamence	Dragon	Flying	Intimidate Moxie (Hidden)	Mega Salamence	Dragon	Flying	Aerilate	Salamencinite
Metagross	Steel	Psychic	Clear Body Light Metal (Hidden)	Mega Metagross	Steel	Psychic	Tough Claws	Metagrossite
Latias	Dragon	Psychic	Levitate	Mega Latias	Dragon	Psychic	Levitate	Latiasite
Latios	Dragon	Psychic	Levitate	Mega Latios	Dragon	Psychic	Levitate	Latiosite
Lopunny	Normal		Cute Charm Klutz Limber (Hidden)	Mega Lopunny	Normal	Fighting	Scrappy	Lopunnite
Garchomp	Dragon	Ground	Sand Veil Rough Skin (Hidden)	Mega Garchomp	Dragon	Ground	Sand Force	Garchompite
Lucario	Fighting	Steel	Steadfast Inner Focus Justified (Hidden)	Mega Lucario	Fighting	Steel	Adaptability	Lucarionite
Abomasnow	Grass	Ice	Snow Warning Soundproof (Hidden)	Mega Abomasnow	Grass	Ice	Snow Warning	Abomasite
Audino	Normal		Healer Regenerator Klutz (Hidden)	Mega Audino	Normal	Fairy	Healer	Audinite
Diancie	Rock	Fairy	Clear Body	Mega Diancie	Rock	Fairy	Magic Bounce	Diancite

Trivia

• Dragon and Psychic appear to be tied as the types with the most Mega Evolutions (eight), while Ice has the fewest (only one).
• So far, the only two Pokémon having two Mega Evolutions are Mewtwo and Charizard. Both of them hail from Kanto and are very popular among Pokémon fans.

Gallery

Mega Mewtwo Y vs. Mega Lucario

Diancie Mega Evolving into Mega Diancie

Charizard's Mega Evolutions, Mega Charizard X and Mega Charizard Y

Steven Stone and Mega Metagross

Shiny Mega Metagross