Breath of Fury, We Ride at Dawn, and The Fire Crystal

Prerequisites

• Breath of Fury on the battlefield
• We Ride at Dawn on the battlefield
• The Fire Crystal on the battlefield

Steps

1. Declare your commander and the creature with Breath of Fury attached as attackers
2. We Ride at Dawn's second ability triggers, creating a 1/1 Mercenary creature token
3. Deal combat damage using the creature that has Breath of Fury attached
4. Breath of Fury triggers, causing you to sacrifice the creature it is attached to, then attach Breath of Fury to the Mercenary token, then causing you to untap all creatures you control and to get an additional combat phase after this one
5. Repeat each combat phase

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite combat phases
• Infinite untap of creatures you control
• Infinite mana creatures you control can produce
• Infinite combat damage