Ashnod's Altar + Dualcaster Mage + Dose of Dawnglow

Ashnod's Altar

Dualcaster Mage

Dose of Dawnglow

How it works

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