Reuniclus

On paper, Reuniclus might seem somewhat mediocre, as it has a relatively poor defensive typing and is easily taken advantage of by some of the most threatening Pokemon in OU, including Bisharp, Weavile, Mega Gyarados, Mega Scizor, and Mega Heracross. It also faces enormous competition as a Calm Mind sweeper with Clefable, which boasts a superior defensive typing. Thankfully, Reuniclus possesses a couple of traits that give it a niche, the first of which is STAB Psyshock. Psyshock allows Reuniclus to do physical damage to targets and thus win Calm Mind wars and easily damage Chansey. Furthermore, Reuniclus's Psychic typing and bulk, while not spectacular, are respectable and allow it to safely check or counter and set up on many offensive Pokemon, including Mega Lopunny, Landorus-T, Mega Medicham, Mega Venusaur, Choice Scarf Heatran, Mega Diancie, and Mega Manectric. Additionally, its Magic Guard ability helps it check offensive teams and defensive teams alike. It renders Reuniclus immune to Stealth Rock as well as Toxic and Leech Seed, which are commonly used as defensive teams' answers to setup sweepers. Reuniclus takes advantage of many defensive Pokemon in OU, such as defensive Mega Altaria, Mega Venusaur, Landorus-T, Ferrothorn, Rotom-W, and Hippowdon, and thus helps out stall teams tremendously when playing against other stall teams.