Thran Vigil + Yahenni, Undying Partisan + Lingering Tormentor

Thran Vigil

Yahenni, Undying Partisan

Lingering Tormentor

How it works

1. Activate Yahenni by sacrificing Lingering Tormentor.
2. When Lingering Tormentor dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. Thran Vigil triggers, putting a +1/+1 counter on Lingering Tormentor.
4. Resolve the Yahenni ability.
5. Repeat.