Venser, Corpse Puppet + Nim Deathmantle + Ashnod's Altar + Core Prowler

Venser, Corpse Puppet

Nim Deathmantle

Ashnod's Altar

Core Prowler

How it works

1. Activate Ashnod's Altar by sacrificing Core Prowler, adding CC.
2. Core Prowler dies, triggering itself and Nim Deathmantle.
3. Resolve the Core Prowler trigger, causing you to proliferate.
4. Venser triggers, creating a legendary 3/3 The Hollow Sentinel artifact creature token.
5. Activate Ashnod's Altar by sacrificing The Hollow Sentinel, adding CC.
6. Resolve the Nim Deathmantle trigger from step 2, causing you to pay 4 to return Core Prowler from your graveyard to the battlefield, and attach Nim Deathmantle to it.
7. Repeat.