Djinn Illuminatus + Pact of the Titan + Pandemonium

Djinn Illuminatus

Pact of the Titan

Pandemonium

How it works

1. Cast Pact of the Titan choosing to pay its replicate cost an arbitrarily large number of times, paying a total of 0.
2. Pact of the Titan's replicate ability triggers, causing you to copy Pact of the Titan for each time the replicate cost was paid.
3. Resolve the first Pact of the Titan, creating a 4/4 Giant creature token.
4. When the Giant enters the battlefield, Pandemonium triggers, dealing damage equal to the Giant's power to any target.
5. Repeat from step 3 for each remaining Pact of the Titan.

With Djinn Illuminatus granting replicate to every instant and sorcery you cast, you can pay a mana cost of zero to copy Pact of the Titan an arbitrarily large number of times without spending an actual fortune. Each of those free copies resolves to flood the board with 4/4 red Giant creature tokens, which conveniently trigger Pandemonium each time they enter the battlefield. This unleashes a devastating wave of direct damage equal to the Giants' power to any target of your choice, completely overwhelming your opponents before the delayed upkeep cost of Pact of the Titan can ever come due to make you lose the game.