Altar of Dementia + Thran Vigil + Lingering Tormentor

Altar of Dementia

Thran Vigil

Lingering Tormentor

How it works

1. Activate Altar of Dementia 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 Altar of Dementia ability.
5. Repeat.

This clever little loop turns Lingering Tormentor into an endless sacrifice engine using Altar of Dementia to mill your opponents out in one fell swoop. Every time the Tormentor goes to the graveyard, its persist ability brings it right back with a -1/-1 counter, which instantly satisfies Thran Vigil's requirement when the creature card leaves the graveyard. Thran Vigil smoothly counters the persist drawback by placing a +1/+1 counter on the Tormentor upon its return, causing the two opposing counters to annihilate each other as a state-based action and leaving the creature completely pristine and ready to be sacrificed all over again.