Pokemon Name: Tyranitar
Moveset Name: TyraniTANK
Move 1: Roar
Move 2: Crunch / Payback
Move 3: Fire Blast / Fire Punch
Move 4: Rest
Item: Leftovers
Ability: Sand Stream
Nature(s): Sassy, Careful
EVs: 252 HP / 94 Defense / 140 Sp. Defence / 24 Speed
What I have here is the next great special wall. I have been using this for months, and is nothing but effective. It's stats at level 100: 404 HP, 279 Def, 298 Sp Def (447 in Sandstorm), 147 Speed, if you choose to use Sassy. I choose to use Sassy over Careful, because with Sassy you can use Fire Blast effectively to hit Skarmory and Forretress for more damage over Fire Punch.
0 SpA Fire Blast vs. 252 HP 0 Sp. Def Skarmory -
66.5% - 78.4%
0 SpA Fire Blast vs. 252 HP 0 Sp. Def Forretress -
141.2% - 167.2% (OHKO every time)
With a Sassy nature, 24 speed evs are needed to outspeed the standard Blissey, which stands no chance against this TyraniTANK. Blissey can't dent this Tyranitar with anything except Seismic Toss or Toxic. When Blissey uses those moves to rack up damage, Rest is there to restore any lost HP. It is wise to pair this Tyranitar up with a Heal Bell or Aromatherapy user. If you choose to leave the 24 Speed evs out, then Payback is the better option for this Tyranitar, but Crunch's defence drops are most welcome.
With Crunch, TyraniTANK becomes the ultimate Latias wall. It can take ANY of Latias's unboosted hits easily, as even Surf will do pitiful amounts of damage. This Tyranitar has no problems switching into a Latias and hitting back with a Super effective Crunch, which also does loads of damage to Celebi.
Timid 252 SpA Surf vs. TyraniTANK - 24.3% - 28.7%
Timid 252 SpA Draco Meteor vs. TyraniTANK - 26.73% - 31.44%
Roar, the icing on the cake. Roar makes this set all the more effective. It can Roar out all types of Special Sweepers, walls and so forth, because he can take a hit. With Stealth Rock support, this Tyranitar is a living hell for the opponent.