Stalwart Successor + Yahenni, Undying Partisan + Obstinate Gargoyle

Stalwart Successor

Yahenni, Undying Partisan

Obstinate Gargoyle

How it works

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