Nihilego

By virtue of its unique typing, great Special Attack and Speed, and vast movepool with coverage and utility, Nihilego carves a niche for itself in UU as a customizable offensive force whose tools can be tailored to its team's needs. Its access to Stealth Rock and Toxic Spikes can allow it to function as a reliable offensive entry hazard setter, using its typing and coverage to threaten out many common entry hazard removers, though it also has the option of running moves such as Protect and Pain Split to more easily work around its checks. Thanks to its typing, coverage, and Speed, Nihilego can also utilize Choice Scarf to revenge kill several of the tier's threatening forces, such as Mega Aerodactyl, Mega Altaria, Terrakion, and Celebi. Moreover, its excellent special bulk for an offensive Pokemon can allow it to sponge weaker or resisted special attacks well, take on Flying-types like Moltres and Togekiss, and blanket check foes like Gengar, Mega Manectric, and Choice Scarf Hydreigon if need be. Unfortunately, Nihilego is at times held back by its terrible physical bulk, which allows the tier's several faster physical threats, including Cobalion and Zeraora, to easily take advantage of it. This also leaves it vulnerable to Pursuit and powerful priority attacks, most notably Scizor's Bullet Punch. It's also unable to power through the tier's surplus of Ground- and Steel-types with its STAB moves alone, which allows most to tank a hit and KO Nihilego with super effective attacks. Nihilego can also struggle to break through a few key defensive Pokemon in the metagame, such as Blissey and Mega Steelix, compromising its wallbreaking capabilities. Lastly, while Nihilego's Speed and typing provide plentiful perks, they also leave it outrun and overwhelmed by a few tier staples, such as Terrakion, Latias, and Cobalion.