Eternal Scourge + Young Deathclaws + Crystalline Crawler + Ashnod's Altar + Innkeeper's Talent

Eternal Scourge

Young Deathclaws

Crystalline Crawler

Ashnod's Altar

Innkeeper's Talent

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 Innkeeper's Talent.
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 Ashnod's Altar by sacrificing Eternal Scourge.
5. Repeat.

This clever loop turns Ashnod's Altar and Crystalline Crawler into a self-sustaining engine by exploiting the unique ability of Eternal Scourge to be cast directly from exile. Young Deathclaws enables this recursive journey by granting Eternal Scourge its scavenge ability, allowing it to be exiled from the graveyard to pump Crystalline Crawler. Because Innkeeper's Talent doubles the counters placed on permanents, that single scavenge dumps six counters onto Crystalline Crawler instead of three. You can then strip those counters for six mana using Crystalline Crawler's own ability, more than enough to recast Eternal Scourge from exile and sacrifice it back to Ashnod's Altar to repeat the cycle with mana to spare.