Mothim

Despite having access to a solid ability in Tinted Lens and STAB moves in Bug Buzz and Air Slash, Mothim is mediocre in PU. It also has access to Quiver Dance, but it is outclassed by Butterfree in this regard. Mothim can function as a decent Choice Specs user; however, this is also done better by Butterfree due to its slightly higher Speed stat. Mothim's horrible defenses and bad Bug / Flying typing, which gives it weaknesses to common attacking types and a 4x weakness to Stealth Rock, make it almost impossible for Mothim to set up and limit its chances to wallbreak. It's outclassed by other special wallbreakers such as Simipour, which are faster and are not hampered by Stealth Rock, and its below-average Speed means that it can easily be taken out by faster Pokemon such as Stoutland.