The Master, Multiplied, Cybermen Squadron, Mycosynth Lattice, and Combat Celebrant

Prerequisites

• The Master, Multiplied on the battlefield
• Cybermen Squadron on the battlefield
• Mycosynth Lattice on the battlefield
• Combat Celebrant on the battlefield
• Opponents cannot block and kill creatures you control
• You have at least two opponents

Steps

1. Declare Combat Celebrant as an attacker, choosing to exert it as it attacks
2. Combat Celebrant's myriad and printed abilities trigger
3. Resolve the myriad trigger, creating a token copy of Combat Celebrant attacking each other opponent
4. Resolve the second trigger, causing you to untap all other creatures you control and to get an additional combat phase after this one
5. Move to your next combat phase, not exiling the Combat Celebrant tokens due to The Master
6. Repeat using a Combat Celebrant token that hasn't attacked this turn

Results

• Infinite combat phases
• Infinite creature tokens
• Infinite ETB