Nim Deathmantle + Ashnod's Altar + Xu-Ifit, Osteoharmonist + Barbarian Class

Nim Deathmantle

Ashnod's Altar

Xu-Ifit, Osteoharmonist

Barbarian Class

How it works

1. Activate Ashnod's Altar by sacrificing another nontoken creature, adding CC.
2. When the creature dies, Nim Deathmantle triggers. Choose not to pay.
3. Activate Xu-Ifit by tapping it, returning a creature from your graveyard to the battlefield.
4. Activate Ashnod's Altar by sacrificing Xu-Ifit, adding CC.
5. When Xu-Ifit dies, Nim Deathmantle triggers, causing you to pay 4 to return it from your graveyard to the battlefield and attach Nim Deathmantle to it.
6. Repeat.