Nim Deathmantle + Ashnod's Altar + Incubator Drone

Nim Deathmantle

Ashnod's Altar

Incubator Drone

How it works

1. Activate Ashnod's Altar by sacrificing Incubator Drone, adding CC.
2. When Incubator Drone dies, Nim Deathmantle triggers, causing you to pay 4 to return Incubator Drone from your graveyard to the battlefield and attach Nim Deathmantle to it.
3. When Incubator Drone enters, it triggers, creating a creature token.
4. Activate Ashnod's Altar by sacrificing a creature token, adding CC.
5. Repeat.

This clever loop turns Ashnod's Altar into a self-sustaining engine by capitalizing on the precise mana values generated upon death. When you sacrifice Incubator Drone to the Altar, its demise triggers Nim Deathmantle while simultaneously refunding two generic mana; the Eldrazi Scion token it leaves behind can then be sacrificed to the Altar as well, yielding the exact four mana needed to pay the Deathmantle's resurrection cost. Because Incubator Drone replaces itself with a token upon entering the battlefield, every single iteration resets the loop, netting you boundless sacrifice triggers, enters-the-battlefield effects, and death triggers without ever running out of resources.