Nim Deathmantle + Dockside Extortionist + Altar of Dementia

Nim Deathmantle

Dockside Extortionist

Altar of Dementia

How it works

1. Activate Altar of Dementia by sacrificing Dockside Extortionist.
2. When Dockside Extortionist dies, Nim Deathmantle triggers, causing you to pay 4 to return Dockside Extortionist from your graveyard to the battlefield, and attach Nim Deathmantle to it.
3. When Dockside Extortionist enters the battlefield, it triggers, creating at least five Treasure tokens.
4. Resolve the Altar of Dementia ability from step 1, causing target player to mill cards equal to Dockside Extortionist's power.
5. Activate four Treasures by tapping and sacrificing them, adding 4.
6. Repeat.