Scizor

Mega Scizor is known for being a great Xerneas check thanks to access to Bullet Punch and a strong base 150 Attack. It also has a great movepool, with access to Roost, Pursuit, U-turn, and a variety of other tricks. U-turn and Roost in particular help Mega Scizor to differentiate itself from other Xerneas checks such as Aegislash; U-turn helps Mega Scizor keep momentum for an offensive team and Roost provides reliable recovery. Mega Scizor is also one of the few viable Pursuit trappers, which is one of the best methods for checking threats such as Mega Gengar, Latios, and Latias. Technician is an ability that would be ineffective on most Pokemon; however, for Mega Scizor it works well due to the low Base Power of its moves. Its Steel / Bug typing has always been an effective defensive typing, granting several resistances and an immunity while leaving a single exploitable 4x weakness to Fire-type moves. Mega Scizor's immunity to Poison allows it to switch into a variety of threats without the fear of being hit with Toxic, which is a great asset to both offensive and defensive teams. However, due to Mega Scizor's exploitable weakness, several Pokemon run Fire-type coverage moves almost exclusively for Mega Scizor, meaning that potential danger is always present. Mega Scizor is also bait to powerful threats such as Ho-Oh and Kyogre, and it can be passive because Steel and Bug are poor types offensively. The lack of Leftovers recovery means that Mega Scizor struggles to maintain ample HP when burned in addition to losing all offensive presence.