Time Sieve + Myr Battlesphere + Extravagant Replication

Time Sieve

Myr Battlesphere

Extravagant Replication

How it works

1. At the beginning of your upkeep, Extravagant Replication triggers, creating a token copy of Myr Battlesphere.
2. The Myr Battlesphere token enters the battlefield, creating four 1/1 Myr creature tokens.
3. Activate Time Sieve by tapping it, sacrificing the Myr Battlesphere token and sacrificing the four Myr tokens, causing you to take an extra turn after this one.
4. Repeat each turn.