Eternal Scourge + Young Deathclaws + Crystalline Crawler + Carrion Feeder + The Earth Crystal

Eternal Scourge

Young Deathclaws

Crystalline Crawler

Carrion Feeder

The Earth Crystal

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 The Earth Crystal.
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 clever loop relies on Young Deathclaws to grant Eternal Scourge scavenge directly from the graveyard, letting you exile it to pump Crystalline Crawler for its full mana cost. Because The Earth Crystal doubles all incoming +1/+1 counters, that single scavenge activation drops twice as many counters onto Crystalline Crawler than normal, generating a surplus of mana when you strip them away for colors. You then recast Eternal Scourge right back from exile using that very mana, only to feed it to Carrion Feeder so it returns to the graveyard to start the cycle anew.