Eternal Scourge + Young Deathclaws + Crystalline Crawler + Branching Evolution + Bloodflow Connoisseur

Eternal Scourge

Young Deathclaws

Crystalline Crawler

Branching Evolution

Bloodflow Connoisseur

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 Branching Evolution.
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 Bloodflow Connoisseur by sacrificing Eternal Scourge.
5. Repeat.

This clever loop turns the graveyard into a recursive engine by using Young Deathclaws to grant Eternal Scourge scavenge, allowing you to continually exile the Scourge to pump up Crystalline Crawler. Because Branching Evolution doubles every counter placed on the Crawler, each scavenge activation generates a massive surplus of counters that you can immediately tap into for any-color mana. You then spend that mana to cast Eternal Scourge straight back out of exile, only to feed it to Bloodflow Connoisseur to reset the whole process while netting endless deaths, enters-the-battlefield triggers, and a growing mountain of power.