Blightbeetle + Blasting Station + Bazaar Trader

Blightbeetle

Blasting Station

Bazaar Trader

How it works

1. Donate Blightbeetle to an opponent
2. Activate Blasting Station by tapping it and 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. When the undying creature enters, Blasting Station triggers, untapping Blasting Station.
5. Resolve the Blasting Station ability from step 2.
6. Repeat from step 2.

This ingenious loop turns an opponent's own defenses against them by utilizing Bazaar Trader to permanently gift Blightbeetle across the table. Once handed over, Blightbeetle's static ability ensures that any creature you control with undying will never receive a +1/+1 counter when returning from the graveyard. This clever interaction allows you to endlessly sacrifice that creature to Blasting Station, triggering the artifact's untap ability upon every re-entry to deal infinite damage to any target.