Blightbeetle + Viscera Seer + Fateful Handoff

Blightbeetle

Viscera Seer

Fateful Handoff

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.

This clever loop hinges on turning Blightbeetle's passive hate into an engine piece by giving the beetle to your opponent using Fateful Handoff, ensuring its static ability prevents +1/+1 counters from being placed on *your* side of the board as well. With that restriction locked in, you can repeatedly sacrifice an undying creature to Viscera Seer, because when that creature tries to return with a +1/+1 counter, Blightbeetle's replacement/prevention effect stops the counter from landing. This leaves the creature permanently vulnerable to dying again, fueling an endless cycle of sacrifices that nets you infinite triggers and infinite scry 1s.