Mikaeus, the Unhallowed + Altar of Dementia + Brambleback Brute

Mikaeus, the Unhallowed

Altar of Dementia

Brambleback Brute

How it works

1. Activate Altar of Dementia by sacrificing Brambleback Brute.
2. When Brambleback Brute dies, its undying ability triggers, returning it from your graveyard to the battlefield without a +1/+1 counter on it due to its replacement effect.
3. Resolve the Altar of Dementia ability
4. Repeat.