Sage of Hours + Cathars' Crusade + Myr Battlesphere + Teleportation Circle

Sage of Hours

Cathars' Crusade

Myr Battlesphere

Teleportation Circle

How it works

1. At the beginning of your end step, Teleportation Circle triggers, blinking Myr Battlesphere.
2. Myr Battlesphere enters the battlefield, triggering itself and Cathars' Crusade.
3. Resolve the Myr Battlesphere trigger, creating four 1/1 Myr creature tokens.
4. The Myr tokens enter the battlefield, triggering Cathars' Crusade four times.
5. Resolve all Cathars' Crusade triggers, putting five +1/+1 counters on each creature you control.
6. Activate Sage of Hours by removing all +1/+1 counters from it, causing you to take at least one extra turn after this one.
7. Repeat each turn.