Mikaeus, the Unhallowed + Phantom Train

Mikaeus, the Unhallowed

Phantom Train

How it works

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