Diancie

Mega Diancie is one of OverUsed's most dangerous Mega Evolutions courtesy of its unique typing, efficient coverage, and critical Speed tier. With its high offensive stats and powerful STAB moves, Mega Diancie can threaten both physical and special walls effectively. Additional coverage in the form of Earth Power and Hidden Power Fire lets it handle many of the common Pokemon that can stomach its STAB attacks. Defensively, Diancie's typing grants it resistances to Fire, Flying, and Dark as well as an immunity to Dragon, letting it check non-Earthquake Mega Charizard X and Dragonite and take crucial attacks such as Talonflame and Volcarona's boosted STAB moves, Mega Pinsir's Quick Attack, and Bisharp's Sucker Punch. Mega Diancie's Speed is one of its most important traits, letting it get the jump on threatening Pokemon that hover on and around the crowded base 100 Speed tier, such as Garchomp, Manaphy, Keldeo, and unboosted Volcarona, as well as Speed tie with Latios and Latias. Magic Bounce allows Mega Diancie to deny entry hazards with proper prediction and shield itself from status moves such as Heatran's Toxic and Taunt, Clefable's Thunder Wave, and Rotom-W's Will-O-Wisp. However, Mega Diancie is burdened with mediocre bulk, and its typing gives it weaknesses to common Water-, Steel-, Grass-, and Ground-type moves, making revenge killers such as Serperior, Weavile, Mega Lopunny, Mega Scizor, and Mega Metagross adept at picking it off. Additionally, Mega Diancie's lack of reliable recovery means it struggles to take strong repeated hits from Pokemon it wants to check, particularly Tornadus-T. Diancie's low Speed before Mega Evolving is also a concern, forcing it to run Protect and forfeit valuable coverage or utility options in order to render its Speed usable the next turn.