Requires

Omarthis, Ghostfire Initiate must be on the battlefield. Mirage Mirror must be on the battlefield. Eldrazi Monument must be on the battlefield. Mirror Gallery must be on the battlefield. You have a way to put a +1/+1 counter on a colorless creature you control. Mana needed:

Steps

1. Put a +1/+1 counter on a colorless creature you control.
2. Omarthis's first triggered ability triggers.
3. In response, activate Mirage Mirror by paying , causing it to become a copy of Omarthis until end of turn.
4. Resolve the Omarthis trigger, putting a +1/+1 counter on itself.
5. Mirage Mirror triggers, putting a +1/+1 counter on itself.
6. Omarthis triggers, putting a +1/+1 counter on itself.
7. Repeat from step 5 any number of times.
8. End the loop by declining to place a +1/+1 counter on a creature.
9. Warning: Omarthis's last ability can increase the risk of losing by drawing from an empty library if you place enough counters on them.

Results