Rhyperior

Rhyperior is a Pokemon of extremes, akin to making a deal with the devil. Rhyperior’s physical stats are only rivaled by Groudon’s in DPP and it has the movepool to back them up. It can 2HKO everything in the tier with a Choice Band with the correct move, while Rock Wrecker is so strong it OHKOes specially defensive Skarmory. Rhyperior gets access to every strong physical coverage move it could want such as Ice Punch, Fire Punch, and Megahorn, while also having Swords Dance to power them up to ludicrous levels. Rhyperior’s Rock / Ground typing is very good offensively while Solid Rock is a fantastic ability to make up for some of its defensive shortcomings, especially physically. Rhyperior can survive Breloom’s Seed Bomb, +1 Tyranitar’s Earthquake, and Gyarados’s +0 Waterfall with minimal investment. Rhyperior is a premier Substitute user alongside paralysis, as very few Pokemon can stomach the correct attack repeatedly, while paralysis lets it outspeed foes.

So why isn’t Rhyperior everywhere in DPP OU and much less common than other Ground-types such as Hippowdon, Swampert, Gliscor, and Flygon? Rhyperior’s Special Defense and Speed are just far too low to make up for the severe defensive flaws from its typing. Rhyperior is one of the slowest Pokemon in the tier; it needs heavy investment even to outspeed minimum Speed Clefable. On top of this, almost all specially offensive Pokemon either can OHKO Rhyperior or put it extremely low on health, even with Solid Rock. Having a 4x weakness to one of the best offensive types in Water as well as Grass alongside weaknesses to Fighting, Steel, Ground, and Ice is debilitating in a tier where these moves are extremely common. Even sand support and Solid Rock are not enough to save Rhyperior from every specially offensive Water-type in the tier, Breloom, Jirachi, Metagross, Latias, and Gengar among many others. While Rhyperior can hit these Pokemon really hard, it is just so slow, to the point even Rock Polish doesn’t let it outspeed slower Choice Scarf users such as Metagross. Other Ground-types may have lower physical stats, but they have far more balanced defenses and not nearly as many weaknesses.