Ashnod's Altar + Nim Deathmantle + Drivnod, Carnage Dominus + Myr Moonvessel

Ashnod's Altar

Nim Deathmantle

Drivnod, Carnage Dominus

Myr Moonvessel

How it works

1. Activate Ashnod's Altar by sacrificing Myr Moonvessel, adding CC.
2. When Myr Moonvessel dies, it and Nim Deathmantle triggers twice.
3. Resolve both Myr Moonvessel triggers, adding CC.
4. Resolve the first Nim Deathmantle trigger, choosing not to pay.
5. Resolve the second Nim Deathmantle trigger, causing you to pay 4 to return Myr Moonvessel from your graveyard to the battlefield, and attach Nim Deathmantle to it.
6. Repeat.

This loop is masterminded by Drivnod, Carnage Dominus, whose static ability doubles every single death trigger your permanents experience. When you feed Myr Moonvessel to Ashnod's Altar for two generic mana, the little artifact creature's own death trigger and Nim Deathmantle's revival ability both trigger twice. The extra mana from the Myr combined with the Altar's sacrifice payout provides the exact four mana needed to pay for the second Nim Deathmantle trigger, returning the Myr to the battlefield and reattaching the Equipment so you can repeat the process indefinitely.