Yenna, Redtooth Regent + Instill Energy + Auratog

Yenna, Redtooth Regent

Instill Energy

Auratog

How it works

1. Activate the mana-producing creature by tapping it, adding at least 2.
2. Activate Yenna by paying 2 and tapping it, creating a token copy of Instill Energy attached to the mana-producing creature, then untapping Yenna and causing you to scry 2.
3. Activate the Instill Energy token by paying 0, untapping the mana-producing creature.
4. Activate Auratog by sacrificing the Instill Energy token, causing Auratog to get +2/+2 until end of turn.
5. Repeat.

This ingenious loop turns Yenna, Redtooth Regent into an enchantment-copying engine by perpetually churning out copies of Instill Energy, whose once-per-turn untap restriction is elegantly bypassed by letting Yenna target and recreate fresh, non-legendary copies of the Aura. While the Instill Energy token handles the untapping, Auratog acts as the vital sacrifice outlet to clear away the old copies so Yenna always has a clean slate. Each iteration feeds the cycle while growing Auratog to infinitely massive proportions and granting you infinite scry 2 triggers to shape the rest of your deck.