Nim Deathmantle + Ashnod's Altar + Nested Shambler

Nim Deathmantle

Ashnod's Altar

Nested Shambler

How it works

1. Activate Ashnod's Altar by sacrificing Nested Shambler, adding CC.
2. When Nested Shambler dies, it and Nim Deathmantle trigger,
3. Resolve the Nested Shambler trigger, creating at least 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 Nested Shambler from your graveyard to the battlefield and attach Nim Deathmantle to it.
6. Repeat.