Blightbeetle + Umbral Collar Zealot + Zedruu the Greathearted

Blightbeetle

Umbral Collar Zealot

Zedruu the Greathearted

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 crafty loop relies on donating **Blightbeetle** to an opponent using **Zedruu the Greathearted**, turning its passive counter-denial into a weapon against them. With **Blightbeetle** permanently parked on their side of the board, an undying creature can loop endlessly when sacrificed to **Umbral Collar Zealot**. Normally, undying would return a creature with a +1/+1 counter and stop it from recurring, but **Blightbeetle** steps in to prevent that counter from ever being placed. This allows the creature to bounce back and forth between the battlefield and the graveyard indefinitely, feeding **Umbral Collar Zealot**'s sacrifice outlet for an infinite stream of triggers and surveils.