Colossal Grave-Reaver + Altar of Dementia + Golgari Thug

Colossal Grave-Reaver

Altar of Dementia

Golgari Thug

How it works

1. Activate Altar of Dementia by sacrificing Golgari Thug.
2. When Golgari Thug dies, it triggers, putting itself from your graveyard onto the top of your library.
3. Resolve the Altar of Dementia ability, causing you to mill cards equal to Golgari Thug's power, ultimately milling Golgari Thug.
4. Colossal Grave-Reaver's second ability triggers, putting Golgari Thug from your graveyard onto the battlefield.
5. Repeat.