Metamorphosis Fanatic + Umbral Collar Zealot + Icewind Stalwart

Metamorphosis Fanatic

Umbral Collar Zealot

Icewind Stalwart

How it works

1. Cast Icewind Stalwart by paying its mana cost.
2. When Icewind Stalwart enters the battlefield, it triggers, targeting Metamorphosis Fanatic.
3. Holding priority, activate Umbral Collar Zealot by sacrificing Icewind Stalwart.
4. Resolve the Icewind Stalwart ability, blinking Metamorphosis Fanatic.
5. When Metamorphosis Fanatic enters the battlefield, it triggers, returning Icewind Stalwart from your graveyard to the battlefield.
6. Repeat from step 2.

This elegant loop relies on the continuous interplay of Icewind Stalwart, Metamorphosis Fanatic, and Umbral Collar Zealot to generate an endless cascade of triggers. By exploiting the stack, you use Umbral Collar Zealot to sacrifice Icewind Stalwart in response to its own entry trigger, sending it to the graveyard just in time for the blinked Metamorphosis Fanatic to resurrect it. Every single iteration of this cycle feeds the sacrifice and surveil engines while endlessly resetting your battlefield.