Primal Prayers + Enduring Renewal + Ashnod's Altar

Primal Prayers

Enduring Renewal

Ashnod's Altar

How it works

1. Cast the creature that causes you to get energy counter(s) when it enters the battlefield by paying E due to Primal Prayers.
2. When the creature enters the battlefield, it triggers, causing you to get at least E.
3. Activate Ashnod's Altar by sacrificing the creature, adding CC.
4. When the creature dies, Enduring Renewal triggers, returning the creature from your graveyard to your hand.
5. Repeat.

This elegant loop turns cheap creature spells into an engine for infinite mana and triggers by exploiting the unique replacement effects of Enduring Renewal alongside Primal Prayers. As you cast your creature using Primal Prayers instead of its mana cost, its entry generates the energy needed to keep the chain going while Ashnod's Altar converts the creature into colorless mana. Whenever that sacrifice sends the creature to your graveyard, Enduring Renewal immediately rescues it back to your hand so you can cast it all over again.