Altar of Dementia + Thran Vigil

Altar of Dementia

Thran Vigil

How it works

1. Activate Altar of Dementia by sacrificing the creature with persist.
2. When that creature 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 that creature.
4. Remove a +1/+1 counter and a -1/-1 counter from that creature as a state-based action.
5. Resolve the Altar of Dementia ability from step 1.
6. Repeat.