Mikaeus, the Unhallowed + Altar of Dementia + Rendclaw Trow

Mikaeus, the Unhallowed

Altar of Dementia

Rendclaw Trow

How it works

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