Mikaeus, the Unhallowed + Cauldron of Souls + Intruder Alarm + Animate Artifact + Carrion Feeder

Mikaeus, the Unhallowed

Cauldron of Souls

Intruder Alarm

Animate Artifact

Carrion Feeder

How it works

1. Activate Carrion Feeder by sacrificing itself.
2. When Carrion Feeder dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
3. When Carrion Feeder enters the battlefield, Intruder Alarm triggers, untapping all creatures.
4. Resolve the Carrion Feeder ability, doing nothing.
5. Activate Cauldron of Souls by tapping it, giving the creature persist until end of turn.
6. Activate Carrion Feeder by sacrificing itself.
7. When Carrion Feeder dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
8. When Carrion Feeder enters the battlefield, Intruder Alarm triggers, untapping all creatures.
9. Resolve the Carrion Feeder ability, doing nothing.
10. Repeat.
11. If you control an additional nontoken, non-Human creature, you may instead sacrifice it to get infinite +1/+1 counters on Carrion Feeder.

This brilliant loop turns the crucible of the graveyard into an endless engine by exploiting the interaction between opposing counters. Mikaeus, the Unhallowed grants undying to your non-Human creatures, while Animate Artifact transforms Cauldron of Souls into a creature so it can untap alongside everything else. When you tap that newly animated Cauldron of Souls to bestow persist, it sets up an alternating dance of death: Carrion Feeder cycles back and forth between undying and persist, canceling out its own +1/+1 and -1/-1 counters each time it dies. Every single iteration of this sacrifice is caught by Intruder Alarm, which untaps your entire board—including your animated artifact—allowing you to feed the loop infinitely and grow your sacrifice outlet without limit.