River Kelpie + Yahenni, Undying Partisan + Hardened Academic

River Kelpie

Yahenni, Undying Partisan

Hardened Academic

How it works

1. Activate Yahenni by sacrificing River Kelpie.
2. When River Kelpie dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. Hardened Academic and River Kelpie trigger.
4. Resolve the Hardened Academic trigger, putting a +1/+1 counter on River Kelpie.
5. Resolve the River Kelpie trigger, causing you to draw a card.
6. Resolve the Yahenni ability
7. Repeat.