Combat Celebrant + Stolen Identity + Mass Hysteria

Combat Celebrant
Stolen Identity
Mass Hysteria

Requires
Combat Celebrant must be on the battlefield. Stolen Identity must be in exile (encoded on another creature you control). Mass Hysteria must be on the battlefield. An opponent cannot block the creature with Stolen Identity encoded and Combat Celebrant.
Steps
  1. Declare Combat Celebrant and the creature with Stolen Identity encoded as attackers, choosing to exert Combat Celebrant as it attacks.
  2. Combat Celebrant triggers, untapping all other creatures you control and to get an additional combat phase after this one.
  3. Deal combat damage to an opponent using the creature that has Stolen Identity encoded.
  4. Stolen Identity triggers, casting a copy of itself without paying its mana cost.
  5. Resolve Stolen Identity, creating a token copy of Combat Celebrant.
  6. Repeat each combat phase using the Combat Celebrant token instead.
Results
Infinite combat damage. Infinite combat phases. Infinite ETB. Infinite LTB. Infinite magecraft triggers. Infinite mana creatures you control can produce. Infinite storm count. Infinite untap of creatures you control.