Szarel, Genesis Shepherd + Crystalline Crawler + Oathsworn Vampire + Phantom Train

Szarel, Genesis Shepherd

Crystalline Crawler

Oathsworn Vampire

Phantom Train

How it works

1. Cast Oathsworn Vampire from your graveyard by paying its mana cost.
2. Activate Phantom Train by sacrificing Oathsworn Vampire.
3. When Oathsworn Vampire is sacrificed, Szarel triggers, putting a number of +1/+1 counters equal to Szarel's power on Crystalline Crawler.
4. Resolve the Phantom Train ability.
5. Activate Crystalline Crawler twice by removing two +1/+1 counters from it, adding 1.
6. Repeat.

This clever loop transforms graveyard recursion and artifact activation into an unstoppable engine of infinite mana and counters. Szarel, Genesis Shepherd plays a pivotal passive role, granting you permission to play lands from your yard while serving as the exponential scaling agent that turns sacrificed permanents into a massive avalanche of +1/+1 counters. By feeding Oathsworn Vampire into Phantom Train, you trigger Szarel, Genesis Shepherd to pump up Crystalline Crawler, whose modular counters can then be stripped away for colored mana. That generated mana instantly pays to recast Oathsworn Vampire—which easily loops right back out of the graveyard thanks to the life you just gained—allowing you to repeat the sacrifice of Phantom Train indefinitely for unbounded colored mana and infinite triggers.