The Pokémon Company International
Mega Evolution Pokémon first made their Pokémon TCG debut as part of the XY expansion, but they work much differently in the new Mega Evolution expansion. Back in the day, unless you had a special Pokémon Tool card known as a Spirit Link attached, your turn would end when you Mega Evolved a Pokémon.
Those Mega Evolution Pokémon-EX also evolved from Basic Pokémon-EX, whereas the latest Mega Evolution Pokémon ex follow the normal rules of Evolution (if that Pokémon evolves). As a result, Mega Evolution Pokémon ex are even more powerful and give up 3 Prize cards when Knocked Out!
—description from the publisher
