Impostor Syndrome, and Aurelia, the Warleader

Prerequisites

• Impostor Syndrome on the battlefield
• Aurelia, the Warleader on the battlefield

Steps

1. Declare Aurelia as an attacker, triggering its ability, causing you to untap all creatures you control and to get an additional combat phase after this one
2. Deal combat damage to an opponent using Aurelia, triggering Impostor Syndrome, creating a token copy of Aurelia that isn't legendary
3. During your next combat phase, declare Aurelia and the Aurelia token as attackers
4. The Aurelia token triggers, causing you to untap all creatures you control and to get an additional combat phase after this one
5. Repeat from step 2

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