Time Sieve, and Cybermen Squadron

Prerequisites

• Time Sieve on the battlefield
• Cybermen Squadron on the battlefield
• You have at least two opponents
• You control a number of nonlegendary artifact creatures that do not have summoning sickness equal to five divided by the number of opponents you have minus one, rounded up
• Opponents cannot block and kill creatures you control

Steps

1. Declare a sufficient number of nonlegendary artifact creatures as attackers
2. Each creature's myriad ability triggers, creating a token copy of each creature attacking each other opponent
3. Activate Time Sieve by tapping it and sacrificing five of the creature tokens, causing you to take an extra turn after this one
4. At end of combat, exile any remaining tokens created by myriad abilities
5. Repeat each turn

Results

• Infinite turns