Combine it with something that gives immunity to black damage or Urza's Armour (reduces all damage taken by 1. And then use pestilence in 1 mana shotsCheesebob said:The Classic:
Pestilence.
It is just so awesome to use when you are losing
EDIT: And then simply spam Pestilence for all it's worth. Very nice in late game when you have over 8 mana/ turn to use. A few dark rituals and you can kill enemies in a single turn