Yenna, Redtooth Regent + Second Wind + Estrid's Invocation

Yenna, Redtooth Regent

Second Wind

Estrid's Invocation

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 Estrid's Invocation. Choose to have Estrid's Invocation enter the battlefield as a copy of Second Wind attached to the mana-producing creature. Then, untap Yenna and scry 2.
3. Activate the Second Wind token's second ability by tapping it, untapping the mana-producing creature.
4. Repeat.