Blightbeetle + Thermopod + Coveted Falcon

Blightbeetle

Thermopod

Coveted Falcon

How it works

1. Activate Coveted Falcon by paying 1, turning it face up.
2. Coveted Falcon triggers, causing an opponent to gain control of Blightbeetle and causing you to draw a card.
3. Activate Thermopod by sacrificing the undying creature.
4. 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.
5. Repeat from step 3.

This clever loop sets up an infinite sacrifice engine by turning the rules of +1/+1 counters against themselves, using Thermopod as both the altar to sacrifice your creatures for red mana and the means to grant them haste. The key to sustaining this cycle relies on Blightbeetle, whose static ability prevents opponents' creatures from receiving +1/+1 counters—which cleverly nullifies the restriction on an undying creature returning from the graveyard, allowing it to keep coming back indefinitely. Meanwhile, Coveted Falcon plays a supporting role here as part of the broader toolkit that this combo utilizes, its disguise and flip mechanics interacting with permanents while the core loop grinds away.