Mikaeus, the Unhallowed + Viscera Seer + Trapjaw Kelpie

Mikaeus, the Unhallowed

Viscera Seer

Trapjaw Kelpie

How it works

1. Activate Viscera Seer by sacrificing Trapjaw Kelpie.
2. When Trapjaw Kelpie dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. Resolve the Viscera Seer ability.
4. Activate Viscera Seer by sacrificing Trapjaw Kelpie.
5. When Trapjaw Kelpie dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
6. Resolve the Viscera Seer ability.
7. Repeat.