Bleezus Azumarill
Azumarill @ Choice Band
Ability: Huge Power
EV's: 172 HP/ 252 Atk/ 84 Spe
Adamant Nature
-Play Rough
-Waterfall
-Aqua Jet
-Knock Off
So I see everybody nominating Pokemon that need Torn-T to help them against certain faster threats and whatever resisted their STABs, and I think to myself about a common pair on offensive teams: Torn + Azu.
AV Tornadus-T is helpful to Azumarill because it puts a lot of pressure on Azu's checks, like threatening to KO Gengar, the Lati's, Mega Venasaur, Amoonguss, Ferrothorn, etc. It also provides something that can switch in and take a hit when Azu needs to kept healthy. Finally, Torn-T's U-Turns help provide Azumarill with the safe switch-ins it needs to demolish teams.
In return, Azumarill hits slower pokemon such as Slowbro, Clefable, and Hippowdon hard, and generally is able to 2HKO many of the fat mons that Torn-T struggles against. It pressures certain offensive threats like ScarfTar and Weavile that prey on Torn-T, and its priority helps beat OU's fastest attackers like Mega Zam, Mega Aero, and Scarf/Sand Rush Exca.
Obviously these mons have difficulty with Pokemon such as Scizor and most electrics; a third member to check those, such as Garchomp, is very helpful.
On a side note, I've used this pair many times on offensive teams to great success.