Eternal Scourge + Young Deathclaws + Crystalline Crawler + Carrion Feeder + Primal Vigor

Eternal Scourge

Young Deathclaws

Crystalline Crawler

Carrion Feeder

Primal Vigor

How it works

1. Activate Eternal Scourge's scavenge ability, granted to it by Young Deathclaws, by paying 3 and exiling Eternal Scourge from your graveyard, putting six +1/+1 counters on Crystalline Crawler due to Primal Vigor.
2. Activate Crystalline Crawler six times by removing six +1/+1 counters from it, adding 6.
3. Cast Eternal Scourge from exile by paying 3.
4. Activate Carrion Feeder by sacrificing Eternal Scourge.
5. Repeat.

This intricate engine turns a modest mana investment into an infinite storm and death loop by constantly recycling a single exile-bound threat. Young Deathclaws grants Eternal Scourge scavenge from the graveyard, allowing you to pay its mana cost and exile it to pump Crystalline Crawler—whose counters are doubled thanks to Primal Vigor. You then cash in those doubled counters for a mana surplus, cast Eternal Scourge right back out of exile, and feed it to Carrion Feeder to reset the loop.