Stalwart Successor + Yahenni, Undying Partisan + Persistent Constrictor

Stalwart Successor

Yahenni, Undying Partisan

Persistent Constrictor

How it works

1. Activate Yahenni by sacrificing Persistent Constrictor
2. When Persistent Constrictor dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. When Persistent Constrictor enters, Stalwart Successor triggers, putting a +1/+1 counter on Persistent Constrictor
4. Resolve the Yahenni ability.
5. Repeat.