Activate Shilgengar by sacrificing the undying creature.
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.
Resolve the Shilgengar ability.
Repeat from step 2.
This fascinating loop relies on **Blightbeetle**’s passive ability to quietly shut down a crucial mechanic, preventing opponents’ creatures from ever receiving +1/+1 counters—which cleverly neuters any negative side effects from recursion. With that prevention in place, you can feed creatures to **Shilgengar, Sire of Famine** to generate a steady stream of Blood tokens while exploiting death triggers. Meanwhile, **Fateful Handoff** provides the clever means of gifting that Blightbeetle directly across the table to ensure the lock is active on your opponent's side.