Blightbeetle + Altar of Dementia + Donate

Blightbeetle

Altar of Dementia

Donate

How it works

1. Donate Blightbeetle to an opponent
2. Activate Altar of Dementia 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 Altar of Dementia ability.
5. Repeat from step 2.

This clever loop relies on *Donate* to permanently gift Blightbeetle to your opponent, turning their side of the board into a hostile environment where +1/+1 counters can never be placed. With that static prevention in place, you can feed any creature with undying to *Altar of Dementia* over and over again; because Blightbeetle stops the counter from landing upon resurrection, the undying trigger keeps resetting endlessly. This fuels an infinite cycle of sacrifices and death triggers that mills your opponent's entire library down to nothing.