Yenna, Redtooth Regent + Ashnod's Altar + Enchanted Evening + Great Oak Guardian

Yenna, Redtooth Regent

Ashnod's Altar

Enchanted Evening

Great Oak Guardian

How it works

1. Activate Yenna by paying 2 and tapping it, creating a token copy of Great Oak Guardian.
2. When the Great Oak Guardian token enters, it triggers, untapping all creatures you control and giving them +2/+2 until end of turn.
3. Activate Ashnod's Altar by sacrificing the Great Oak Guardian token, adding CC.
4. Repeat.

This engine transforms the battlefield into a self-sustaining loop by turning every permanent you own into an enchantment via Enchanted Evening. Once that global shift is in place, Yenna, Redtooth Regent can repeatedly copy Great Oak Guardian—a feat made possible because Enchanted Evening strips away the Guardian's original card type uniqueness or simply lets Yenna target it safely as an enchantment. Each time the Great Oak Guardian token enters the battlefield, its trigger untaps Yenna and your other creatures, allowing you to feed the token to Ashnod's Altar for more colorless mana to fuel Yenna's ability all over again.