Yenna, Redtooth Regent + Instill Energy + Thaumatog

Yenna, Redtooth Regent

Instill Energy

Thaumatog

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 Thaumatog's second ability by sacrificing the Instill Energy token, causing Thaumatog to get +1/+1 until end of turn.
5. Repeat.

This ingenious loop transforms Yenna, Redtooth Regent into an enchantment-duplicating engine by leaning entirely on Instill Energy to constantly untap her. Because Yenna's ability untaps herself and triggers a scry whenever she copies an Aura, duplicating Instill Energy creates a renewable, zero-cost untap effect for whatever creature it enchants. Meanwhile, Thaumatog acts as the ultimate payoff by devouring those excess enchantment tokens, turning each copied Aura into permanent-buffing fuel for an infinitely large creature.