Stalwart Successor + Phyrexian Altar

Stalwart Successor

Phyrexian Altar

How it works

1. Activate Phyrexian Altar 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. Repeat.