Slow, sandy, poison death:

Careful-BrightPowder
-Rock Tomb
-Toxic
-Sandstorm
-Substitute

This one's designed to take advantage of it's ability to slowly chip away at enemies. It first poisons the enemy with Toxic. It then uses Sandstorm. It creates a substitue, and every turn after that, uses Rock Tomb, slowing the opponent's speed. Careful is the perfect nature for this, because it raises defense, and lowers Sp. Attack, which this set doesn't even use.