Nim Deathmantle + Ashnod's Altar + Triplicate Titan

Nim Deathmantle

Ashnod's Altar

Triplicate Titan

How it works

1. Activate Ashnod's Altar by sacrificing Triplicate Titan, adding CC.
2. When Triplicate Titan dies, it and Nim Deathmantle trigger,
3. Resolve the Triplicate Titan trigger, creating three creature tokens.
4. Holding priority, activate Ashnod's Altar by sacrificing a creature token, adding CC.
5. Resolve the Nim Deathmantle trigger, causing you to pay 4 to return Triplicate Titan from your graveyard to the battlefield and attach Nim Deathmantle to it.
6. Repeat.