Stalwart Successor + Spawning Pit

Stalwart Successor

Spawning Pit

How it works

1. Activate Spawning Pit 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 Spawning Pit ability.
6. Repeat.