MAGIC: THE GATHERING
Pact of Negation is blue.
Counter target spell.
At the beginning of your next upkeep, pay . If you don't, you lose the game.
Free counter magic is powerful stuff. Pact of Negation is a great target for Cunning Wish, allowing you to find a counter spell at instant speed. You can even tutor up Pact of Negation with Tolaria West.