Gardevoir

Mega Gardevoir is a dangerous wallbreaker in Battle Spot Singles, capable of threatening most switch-ins with powerful Pixilate-boosted Hyper Voices. Its Psychic typing sets it apart from other Fairy-types such as Sylveon, preventing it from being a safe switch-in for Poison-types like Gengar and Mega Venusaur that struggle to survive STAB Psyshock. A useful ability in Trace also allows it to copy more useful abilities such as Speed Boost and Intimidate before Mega Evolving, which it can then use against the foe. Beyond functioning as a wallbreaker as a Mega Evolution, Gardevoir can also run a Choice Scarf set to function as a revenge killer with moderate surprise factor, as most opponents will expect a Gardevoir to Mega Evolve.

Gardevoir is somewhat reliant on speed control such as paralysis support, since base 100 is a risky Speed tier for such a physically frail Mega Evolution. This makes it easy to revenge kill Gardevoir with priority or just fast physical attackers. Speed tying with Mega Kangaskhan and being outsped by Garchomp also make it difficult for Mega Gardevoir to threaten some of the most common Pokemon even though few things can switch into Pixilate Hyper Voice. As a Mega Evolution, it relies more on team support than the likes of Mega Kangaskhan and Mega Blaziken to be successful, while Sylveon gives it competition as a special Fairy-type without requiring a Mega Stone.