Dualcaster Mage + Persist + Carrion Feeder

Dualcaster Mage

Persist

Carrion Feeder

How it works

1. Cast Persist by paying its mana cost, targeting any applicable target.
2. Holding priority, cast Dualcaster Mage by paying its mana cost.
3. When Dualcaster Mage enters, it triggers, targeting Persist.
4. Holding priority, activate Carrion Feeder by sacrificing Dualcaster Mage.
5. Resolve the Dualcaster Mage trigger, copying Persist, with the copy targeting Dualcaster Mage
6. Resolve the Persist copy, returning Dualcaster Mage from your graveyard to the battlefield.
7. Repeat from step 3.

This clever loop sets up an infinite engine by leveraging a classic copy-and-recursion synergy, legal in commander, legacy, oathbreaker, and vintage. You begin by casting Persist to target a creature, then interrupt it with Dualcaster Mage whose entry trigger copies that very same spell. Meanwhile, Carrion Feeder acts as the designated sacrificial altar, letting you feed Dualcaster Mage back to the graveyard so it can be endlessly resurrected by the copied recursion spell while building up infinite +1/+1 counters on itself.