Stalwart Successor + Phantom Train

Stalwart Successor

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. When that creature enters, Stalwart Successor triggers, putting a +1/+1 counter on it.
4. Remove a +1/+1 and a -1/-1 counter from that creature as a state-based action.
5. Resolve the Phantom Train ability.
6. Repeat.