Yore-Tiller Nephilim + Medomai the Ageless + Altar of Dementia

Prerequisites

• An opponent cannot block creatures you control.

Steps

1. 1Declare Yore-Tiller Nephilim as an attacker.
2. 2Yore-Tiller Nephilim triggers, returning Medomai from your graveyard to the battlefield tapped and attacking.
3. 3Deal combat damage using Medomai, triggering its ability, causing you to take an extra turn after this one.
4. 4Activate Altar of Dementia by sacrificing Medomai.
5. 5Repeat each turn.

Effects

• Infinite turns
• Lock