Virizion

Virizion stands out for its near-unique ability to check Mega Kangaskhan, Landorus-T, and Water-types in one slot. Virizion is able to check Mega Kangaskhan reliably thanks to its base 108 Speed and a powerful Close Combat. Landorus-T is manipulated by Virizion's presence, as Landorus-T gives either Virizion or Virizion's partner the ability to attack, unthreatened. Virizion's fantastic Special Defense lets it take on many special attackers without any investment, the Water-types primarily. Being a Grass-type, Virizion is immune to Rage Powder, allowing it to ignore Amoonguss's redirection, which can be useful. While it's not the primary reason for Virizion's usage, Virizion can provide decent support in Quick Guard and Taunt. Quick Guard can shut down the many priority-centered Pokemon of the Battle Spot Doubles format, such as Thundurus, whereas Taunt can cripple support Pokemon, such as Clefable, as well as Aegislash, which is reliant on King's Shield.

The main limiting factor to Virizion's success is its mediocre attacking stats; both its Attack and Special Attack sit at base 90, which means that Virizion is reliant on its Life Orb in order to deal consistent damage. Virizion is weak to many common offensive Fire-, Ice-, Flying-, and Fairy-types primarily. This is only compounded by Virizion's poor coverage, STAB or otherwise, leaving Virizion no way to hit common Pokemon such as Aegislash, Gengar, Mega Salamence, and Amoonguss. These two factor combine to make Virizion very easy to check, even unintentionally.