Breath of Fury, Donatello, Gadget Master, and Garna, the Bloodflame

Prerequisites

• Breath of Fury on the battlefield
• Donatello, Gadget Master on the battlefield
• Garna, the Bloodflame on the battlefield

Steps

1. Deal combat damage to an opponent using Donatello and the creature that has Breath of Fury attached, triggering Donatello and Breath of Fury
2. Resolve the Donatello trigger, creating a token copy of the artifact creature
3. Resolve the Breath of Fury trigger, causing you to sacrifice the creature it is attached to, then attach Breath of Fury to the artifact creature token, then causing you to untap all creatures you control and to get an additional combat phase after this one
4. Repeat each combat phase

Results

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