Primo, the Unbounded + Breath of Fury + Concordant Crossroads

Prerequisites

• Breath of Fury attached to another creature you control that has base power 0.
• An opponent cannot block creatures you control.

Steps

1. 1Deal combat damage to an opponent using the creature that has Breath of Fury attached, triggering Breath of Fury and Primo.
2. 2Resolve the Primo trigger, creating a 0/0 Fractal creature token that enters with a number of +1/+1 counters on it equal to the damage dealt.
3. 3Resolve the Breath of Fury trigger, causing you to sacrifice the creature it is attached to and attach it to the Fractal token, then causing you to untap all creatures you control and to get an additional combat phase after this one.
4. 4Repeat each combat phase.

Effects

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