Mikaeus, the Unhallowed + Bartolomé del Presidio + Grazing Kelpie

Mikaeus, the Unhallowed

Bartolomé del Presidio

Grazing Kelpie

How it works

1. Activate Bartolomé del Presidio by sacrificing Grazing Kelpie.
2. When Grazing Kelpie dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. Resolve the Bartolomé del Presidio ability.
4. Activate Bartolomé del Presidio by sacrificing Grazing Kelpie.
5. When Grazing Kelpie dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
6. Resolve the Bartolomé del Presidio ability.
7. Repeat.

This clever loop leverages counter-cancellation mechanics to continuously recycle Grazing Kelpie through your graveyard. By utilizing the passive buffs from Mikaeus, the Unhallowed, Grazing Kelpie alternates between triggering undying and persist whenever it is sacrificed to Bartolomé del Presidio. Because +1/+1 and -1/+1 counters annihilate each other upon entering the creature, the Kelpie never accumulates a permanent stockpile of counters, allowing you to feed this engine indefinitely for limitless sacrifices and enter-the-battlefield triggers.