Massimo, the Magician, Combat Celebrant, Rising of the Day, and Splash Portal

Prerequisites

• Massimo, the Magician in hand or in the command zone
• Combat Celebrant on the battlefield
• Rising of the Day on the battlefield
• Splash Portal in the graveyard
• plus commander tax if applicable available

Steps

1. Cast Massimo by paying its mana cost plus commander tax if applicable
2. When Massimo enters, it triggers, exiling Splash Portal from your graveyard and giving Massimo the listed ability
3. Declare Massimo and Combat Celebrant as attackers, choosing to exert Combat Celebrant as it attacks
4. Combat Celebrant triggers, untapping all other creatures you control and causing you to get an additional combat phase after this one
5. Deal combat damage with Massimo
6. Its ability triggers, casting a copy of Splash Portal from exile without paying its mana cost
7. Resolve Splash Portal, blinking Combat Celebrant
8. Repeat from step 3 each combat phase

Results

• Infinite combat damage
• Infinite combat phases
• Infinite creature ETB
• Infinite creature LTB
• Infinite magecraft triggers
• Infinite mana creatures you control can produce
• Infinite storm count
• Infinite untap of creatures you control