Yore-Tiller Nephilim, Medomai the Ageless, and Umbral Collar Zealot

Prerequisites

• Yore-Tiller Nephilim on the battlefield
• Medomai the Ageless in the graveyard
• Umbral Collar Zealot on the battlefield

Steps

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

Results

• Infinite turns
• Lock