Blightbeetle + Umbral Collar Zealot + Harmless Offering

Blightbeetle

Umbral Collar Zealot

Harmless Offering

How it works

1. Donate Blightbeetle to an opponent
2. Activate Umbral Collar Zealot by sacrificing the undying creature.
3. When the undying creature dies, its undying ability triggers, returning itself from your graveyard to the battlefield without a +1/+1 counter on it due to Blightbeetle.
4. Resolve the Umbral Collar Zealot ability.
5. Repeat from step 2.

This clever loop locks your opponent out of growing their own threats while setting up a continuous engine for your own board. By casting Harmless Offering, you saddle your opponent with Blightbeetle, whose static ability ensures that +1/+1 counters can never be placed on any creatures your opponents control. Once that tax is in place, you can continually activate Umbral Collar Zealot by sacrificing an undying creature to filter your library with surveil. Because Blightbeetle strips away the intended downside of the undying mechanic, your sacrificed creature returns to the battlefield completely free of counters, ready to be fed back into the Zealot's maw for infinite sacrifices, triggers, and graveyard setup.