Altar of Dementia, Trapjaw Kelpie, and Hardened Academic

Prerequisites

• Altar of Dementia on the battlefield
• Trapjaw Kelpie on the battlefield
• Hardened Academic on the battlefield

Steps

1. Activate Altar of Dementia by sacrificing Trapjaw Kelpie
2. When Trapjaw Kelpie dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
3. Hardened Academic triggers, putting a +1/+1 counter on Trapjaw Kelpie
4. Resolve the Altar of Dementia ability
5. Repeat

Results

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