Nim Deathmantle + Ashnod's Altar + Ambitious Aetherborn

Nim Deathmantle

Ashnod's Altar

Ambitious Aetherborn

How it works

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

This looping engine relies on Ashnod's Altar to convert your creatures into the exact mana needed to keep the cycle spinning. Whenever you sacrifice Ambitious Aetherborn to the Altar, Nim Deathmantle steps in to resurrect it, feeding right back into the mana generated by the Altar plus the sacrifice of the Servo token produced by the Aetherborn's fabricate ability. Because the Altar provides four total colorless mana across the two sacrifices—exactly matching the four-mana resurrection cost—you achieve a self-sustaining loop that floods the battlefield with endless entries and sacrifices.