With blessing from PK Gaming, I give thee... Garchomp.
With the banning of Sand Veil under a revised Evasion Clause, the infamous Mach Pokémon returns to rampage in OU. His nearly-unresisted STAB coverage and excellent Attack and Speed stats provides him with an always terrifying offensive presence, and with bulk practically unheard of on a Pokémon as powerful as Garchomp, stopping him in the middle of a sweep is no mean feat. Garchomp's Ground-subtyping is even more of a blessing, providing immunity to Electric attacks such as Thunder, Volt Switch, Thunder Wave, and a resistance to Stealth Rock, giving him switch-in opportunities his Flying brothers would rage for.
Garchomp's versatility is not to be underestimated either. His fantastic base 108 HP and 95/85 defenses gives him better all-around bulk than Swampert! Garchomp was given every tool he needs to succeed as a defensive pivot and harasser in the generation shift: Rough Skin ensures any physical attacker will be wishing they had stayed home; Dragon Tail gives Garchomp a powerful phazing tool, which mixes perfectly with Stealth Rock, a gift from the Black and White 2 Move Tutors. His excellent base 102 speed even makes Garchomp quite possibly the most devastating RestTalk phazer in the game, as opposing attackers will find him far sturdier than other Pokémon as powerful and walls that can take his punishment will quickly find themselves returned to their Pokéballs only to take more damage upon re-entry.
As incredible as we've painted Garchomp to be, and he most certainly is incredible, he has his fair share of shortcomings. The most obvious is the absence of Sand Veil, and the free turns it provides. Despite his unique speed, the only 102 Pokémon in the game, it's just not as fast as it once was, especially with Keldeo, Terrakion, and the twin Eon Pokémon running amok. Finally, his Ground-subtyping removes his resistances to Water- and Grass-type attacks, which are always dangers in the weather-torn OU metagame, as well as compounding Dragon's fatal Ice weakness.