Latios

Mega Latios's great Speed tier and offensive stats make it a premier check to several threats in the OU metagame such as Heatran, Landorus-T, and Gliscor. Moreover, its excellent offensive typing, high-powered STAB attacks, and vast range of coverage options make Latios a formidable offensive threat in its own right, able to threaten defensive staples like Toxapex, Gliscor, Mega Venusaur, and Zapdos. Mega Latios also sports numerous type resistances, great bulk, and access to recovery, enabling it to act as a solid pivot into Water-, Grass-, Electric-, and Fire-type attacks. Additionally, Mega Latios's naturally high Attack and access to Earthquake allows it to 2HKO common Psychic-type checks such as Heatran, Assault Vest Magearna, and Tyranitar after Stealth Rock and Spikes damage. Despite its strengths, though, Mega Latios is threatened by common Fairy-types in the tier such as Tapu Lele, Mega Mawile, and Magearna and walled by Steel-types like Ferrothorn, Celesteela, and Mega Scizor. Mega Latios is also troubled by faster offensive threats such as Greninja, Tapu Koko, and Mega Alakazam and is highly vulnerable to Pursuit trappers like Tyranitar and Weavile.