Dualcaster Mage + Corpse Dance + Yahenni, Undying Partisan

Dualcaster Mage

Corpse Dance

Yahenni, Undying Partisan

How it works

1. Cast Corpse Dance 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 Corpse Dance.
4. Holding priority, activate Yahenni by sacrificing Dualcaster Mage.
5. Resolve the Dualcaster Mage trigger, copying Corpse Dance, with the copy targeting Dualcaster Mage
6. Resolve the Corpse Dance copy, returning Dualcaster Mage from your graveyard to the battlefield.
7. Repeat from step 3.

This elegant loop transforms a graveyard recursion spell into an endless engine by using Dualcaster Mage to continuously copy Corpse Dance from exile or the graveyard, netting you endless creature sacrifices, enters-the-battlefield, and death triggers. While Dualcaster Mage pulls the heavy lifting by copying the spell on entry, Yahenni, Undying Partisan serves as the vital sacrifice outlet to send the Mage right back where it needs to be. Furthermore, Yahenni's passive ability happily grows with every loop iteration, turning your infinite sacrifice loop into an arbitrarily massive threat.