Blightbeetle + Ashnod's Altar + Coveted Falcon

Blightbeetle

Ashnod's Altar

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 Ashnod's Altar 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 turns Coveted Falcon into a perpetual-motion machine by repeatedly handing your own Blightbeetle away and taking it back, fueled entirely by the mana-generating power of Ashnod's Altar. The real genius here is Blightbeetle's passive static ability, which prevents your opponents' creatures from receiving +1/+1 counters; this cleanly shuts down any undying counter-placement that would normally stop the loop from repeating. As you sacrifice your creatures and watch them return endlessly to the battlefield, you'll generate infinite colorless mana alongside an avalanche of sacrifice, death, and entry triggers.