Be warned as this is not 100% confirmed at this time. First off are various "Mega" forms of various Pokémon, specifically MegaBlaziken, MegaAbsol, MegaMawile, MegaMewtwo, MegaLucario and MegaAmpharos. They're all called "Mega". MegaMawile is Steel/Fairy-type, as is normal Mawile now. MegaMawile has the ability Huge Power. MegaBlaziken has Speed Boost
They "evolve" through a process called "Mega Evolution"
Bit skeptical myself considering how over-powered Blaziken is already but they do look pretty sweet.