Emptiness + Phyrexian Altar + Coati Scavenger

Emptiness

Phyrexian Altar

Coati Scavenger

How it works

1. Cast Emptiness for its evoke cost by paying .
2. When Emptiness enters, its first ability and evoke ability trigger.
3. Holding priority, activate Phyrexian Altar by sacrificing Emptiness, adding .
4. Resolve Emptiness's evoke trigger, failing to sacrifice it as it's no longer on the battlefield.
5. Resolve Emptiness's first trigger, returning Coati Scavenger from your graveyard to the battlefield.
6. When Coati Scavenger enters, it triggers, returning Emptiness from your graveyard to your hand.
7. Activate Phyrexian Altar by sacrificing Coati Scavenger, adding .
8. Repeat.

This elegant loop relies on the clever interaction of evoking Emptiness for `{W}{W}` so that it triggers its own graveyard return before the sacrifice clause can catch up to it. By sacrificing Emptiness to Phyrexian Altar in response, you bank the mana needed to replay it while sending it straight to the graveyard, where its entrance trigger plucks Coati Scavenger back to your hand. When Coati Scavenger hits the battlefield, its descend ability instantly retrieves Emptiness to your hand, and sacrificing Coati Scavenger back to Phyrexian Altar resets the entire cycle.