Altar of Dementia + Gravelgill Axeshark + Mikaeus, the Unhallowed

UB identity

Commander legal

The 3 combo pieces

• Altar of Dementia
• Gravelgill Axeshark
• Mikaeus, the Unhallowed

How to execute it

1. Activate Altar of Dementia by sacrificing Gravelgill Axeshark.
2. When Gravelgill Axeshark 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 Gravelgill Axeshark.
5. When Gravelgill Axeshark 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.

What the combo produces

• Infinite creature LTB
• Infinite death triggers
• Infinite ETB
• Infinite mill
• Infinite sacrifice triggers
• Infinite self-mill