Dualcaster Mage + Second Sunrise + Yahenni, Undying Partisan

Dualcaster Mage

Second Sunrise

Yahenni, Undying Partisan

How it works

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

This ingenious loop turns a simple recursion spell into an endless engine by using Dualcaster Mage to continuously copy Second Sunrise from the graveyard back to your hand and battlefield. As you cycle through your spells, Yahenni, Undying Partisan serves as the mandatory sacrifice outlet that bins your Mage each iteration while safely growing larger with +1/+1 counters. Because Second Sunrise brings back everything that hit the graveyard that turn, both your mage and your sacrifice fodder return ready to repeat the cycle indefinitely.