Mesprit

Mesprit is a very niche Stealth Rock setter with near-perfect coverage to threaten opposing entry hazard removers and Stealth Rock setters, allowing it to act as an offensive support Pokemon. It also has good uninvested bulk and a useful ability that let it find multiple opportunities to set up Stealth Rock. Outside of this role, however, Mesprit is horribly outclassed by other Stealth Rock setters such as Druddigon, Rhydon, and Seismitoad because they're far more consistent and have better defensive utility by virtue of their types, bulk, and abilities. Other Psychic-types such as Medicham, Delphox, and Sigilyph also give Mesprit competition, as they are stronger and the latter two have better Speed tiers to make them more threatening. While it sports good bulk, Mesprit's lack of reliable recovery combined with the necessity to run full offensive investment to have any valuable niche makes it susceptible to being worn down quickly. Mesprit also only has average Speed and is outpaced by faster threats such as Rotom, Togedemaru, and Sneasel.