Lesser Masticore + Thran Vigil + Phantom Train

Lesser Masticore

Thran Vigil

Phantom Train

How it works

1. Activate Phantom Train 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. Thran Vigil triggers, putting a +1/+1 counter on Lesser Masticore.
4. Resolve the Phantom Train ability.
5. Repeat.

This crafty loop turns Phantom Train into a sacrifice outlet that feeds on Lesser Masticore over and over, generating an endless stream of entries, leaves, and deaths. Because Lesser Masticore returns via persist with a -1/-1 counter, Thran Vigil steps in during your turn to place a +1/+1 counter on it whenever it leaves the graveyard, which immediately cancels out the -1/-1 counter through state-based actions. This counter neutralization resets the Masticore so it can be sacrificed again, letting you pile infinite +1/+1 counters onto your creatures while triggering your entire death-and-sacrifice engine indefinitely.