Gideon of the Trials + Magus of the Mirror + Cavern Harpy

Gideon of the Trials

Magus of the Mirror

Cavern Harpy

How it works

1. During your upkeep, activate Cavern Harpy by paying 1 life.
2. Repeat step 1 until you have zero life.
3. Resolve the last Cavern Harpy trigger, returning it to your hand.
4. The remaining Cavern Harpy triggers fizzle.
5. Activate Magus of the Mirror by tapping and sacrificing it, exchanging your life total with an opponent.
6. The opponent loses the game due to having zero life.