Szarel, Genesis Shepherd + Crystalline Crawler + Umbral Collar Zealot + Bloodsoaked Champion

Szarel, Genesis Shepherd

Crystalline Crawler

Umbral Collar Zealot

Bloodsoaked Champion

How it works

1. Activate Bloodsoaked Champion by paying 1, returning it from your graveyard to the battlefield.
2. Activate Umbral Collar Zealot by sacrificing Bloodsoaked Champion.
3. When Bloodsoaked Champion is sacrificed, Szarel triggers, putting a number of +1/+1 counters equal to Szarel's power on Crystalline Crawler.
4. Resolve the Umbral Collar Zealot ability.
5. Activate Crystalline Crawler twice by removing two +1/+1 counters from it, adding 1.
6. Repeat.

This engine turns a simple recursive loop into an unstoppable growth machine by using Bloodsoaked Champion as a recurring sacrifice fodder for Umbral Collar Zealot. Every time the Champion hits the graveyard, Szarel, Genesis Shepherd triggers off the sacrifice, pumping those deaths directly into Crystalline Crawler by distributing a massive payload of +1/+1 counters based on Szarel's power. Those counters aren't just for show; you simply peel them right back off Crystalline Crawler to generate the exact mana needed to pay the raid cost and bring Bloodsoaked Champion right back to the battlefield, fueling an infinite loop that leaves you with unbounded mana, surveils, and counters.