When it debuted in X and Y, Greninja became a competitive powerhouse due to its hidden ability, Protean, which changes the user's type to make every single move receive STAB (same type attack bonus).

Popularity and design flaws may warrant Mega Evolutions for starters like Serperior, Infernape, and Greninja ... receive a Mega Evolution is the grass type, Seperior. The single grass type is ...