Dex Entry Concept from an edited image I made on Pixlr. Here is Mega Espeon.
Mega Espeon:
Type: Psychic/Steel
Ability: Esper Boost
Esper Boost combines the effects of numerous powerful abilities into one overwhelming psychic mutation. The immense energy produced by Mega Espeon's two gems constantly enhances its body, mind, and defenses.
(Magic Bounce + Psychic Surge + Beast Boost + Ability Equivalence of Miracle Eye + Earth Eater + Cursed Body + Huge Power + Speed Boost + Wonder Guard + Sturdy + Protean + Flash Fire)
The mutation of its original forehead gem caused a second gem to grow above its head, becoming a vast reservoir for psychic energy. The gem is said to be harder than diamond and can store an immense amount of power without cracking. Its three tails have hardened into golden, metallic structures that help regulate and discharge the excess energy flowing through its body.
Mega Espeon can sense the emotions of those around it and is especially sensitive to the feelings of its Trainer. When its bond with its Trainer is strong, the overwhelming energy inside its head becomes easier to control, allowing it to perform feats of telekinesis powerful enough to move enormous objects. The psychic energy released by its gem can also reinforce its body, making it exceptionally difficult to injure.
Despite its tremendous strength, Mega Espeon suffers from severe migraines caused by the unstable growth of its second gem. When it is surrounded by someone it deeply trusts, however, the pain gradually subsides. It is said that a Mega Espeon with a truly powerful bond can fight without feeling the gem's agony at all.
The immense pain caused by the mutation forces its body to produce far more psychic energy than a normal Mega Evolution can withstand. As a result, Mega Espeon's true power is said to surpass that of ordinary Mega-Evolved Pokémon, making it one of the most powerful Mega Evolutions ever recorded.
Base Stats:
HP: 65
Attack: 70
Defense: 115
Special Attack: 155
Special Defense: 130
Speed: 125
Total: 660
