Szarel, Genesis Shepherd + Cauldron of Souls + Clock of Omens + Sarcatog

Szarel, Genesis Shepherd

Cauldron of Souls

Clock of Omens

Sarcatog

How it works

1. Activate Cauldron of Souls by tapping it, giving two nontoken artifact creatures persist until end of turn.
2. Activate Clock of Omens by tapping the nontoken artifact creatures, untapping Cauldron of Souls.
3. Activate Sarcatog by sacrificing one of the nontoken artifact creatures that doesn't have a -1/-1 counter on it.
4. When the creature dies, its persist ability and Szarel triggers.
5. Resolve the persist trigger, returning the creature from your graveyard to the battlefield.
6. Resolve the Szarel trigger, putting a number of +1/+1 counters on the other artifact creature.
7. Resolve the Sarcatog ability.
8. Repeat from step 3 once, instead sacrificing the creature who had counters placed on it in step 6.
9. Repeat from step 1.

This clever loop transforms a graveyard and a handful of artifacts into an unstoppable engine, relying on Cauldron of Souls to grant persist to your key players. You use Clock of Omens to tap those artifact creatures and repeatedly untap the Cauldron, allowing Sarcatog to sacrifice them on command. As they perish and return with -1/-1 counters, Szarel, Genesis Shepherd steps in to place massive +1/+1 counters on the survivors—instantly neutralizing those pesky -1/-1 counters and setting up the next sacrifice.