Nim Deathmantle + Ashnod's Altar + Conscripted Infantry

Nim Deathmantle

Ashnod's Altar

Conscripted Infantry

How it works

1. Activate Ashnod's Altar by sacrificing Conscripted Infantry, adding CC.
2. Conscripted Infantry dies, triggering itself and Nim Deathmantle.
3. Resolve the Conscripted Infantry trigger, creating a 1/1 Soldier artifact creature token.
4. Activate Ashnod's Altar by sacrificing the Soldier, adding CC.
5. Resolve the Nim Deathmantle trigger from step 2, causing you to pay 4 to return Conscripted Infantry from your graveyard to the battlefield, and attach Nim Deathmantle to it.
6. Repeat.