Blightbeetle + Viscera Seer + Harmless Offering

Blightbeetle

Viscera Seer

Harmless Offering

How it works

1. Donate Blightbeetle to an opponent
2. Activate Viscera Seer 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 Viscera Seer ability.
5. Repeat from step 2.

By casting Harmless Offering to hand over Blightbeetle to your opponent, you completely neutralize their green cards while weaponizing its passive ability against them. With Blightbeetle on their side of the board preventing +1/+1 counters from being placed on their creatures, any creature with undying that you sacrifice to Viscera Seer will continually return without the counter that would normally shut the loop down. This lets you cycle your sacrificial fodder through Viscera Seer an infinite number of times, generating boundless death triggers and endless scrys to sculpt your hand.