Captain Storm, Cosmium Raider + Lesser Masticore + Umbral Collar Zealot + Xenograft

Captain Storm, Cosmium Raider

Lesser Masticore

Umbral Collar Zealot

Xenograft

How it works

1. Activate Umbral Collar Zealot by sacrificing Lesser Masticore.
2. When Lesser Masticore dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. When Lesser Masticore enters the battlefield, Captain Storm triggers, putting a +1/+1 counter on Lesser Masticore.
4. Resolve the Umbral Collar Zealot ability.
5. Repeat.

This loop turns Lesser Masticore into an endlessly recurring sacrifice engine by letting its persist mechanic continuously bring it back from the dead. Because Xenograft redefines every creature you control as a Pirate, Captain Storm, Cosmium Raider is able to step in and place a +1/+1 counter on the Masticore the moment it re-enters, instantly neutralizing its incoming -1/-1 counter so the persist trigger will work again next time. Finally, Umbral Collar Zealot provides the sacrifice outlet that kicks off the loop while letting you surveil through your entire deck in the process.