Activate Viscera Seer by sacrificing River Kelpie.
When River Kelpie dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
Hardened Academic and River Kelpie trigger.
Resolve the Hardened Academic trigger, putting a +1/+1 counter on River Kelpie.
Resolve the River Kelpie trigger, causing you to draw a card.
Resolve the Viscera Seer ability
Repeat.
This clever loop relies on a persistent death-and-rebirth cycle orchestrated by Viscera Seer, which sacrifices River Kelpie to repeatedly trigger its persist ability. Every time River Kelpie leaves the graveyard, Hardened Academic steps in with its static-adjacent triggered ability, placing a +1/+1 counter on River Kelpie that immediately cancels out its incoming -1/+1 counter. This counter neutralization keeps River Kelpie primed to persist indefinitely while simultaneously fueling River Kelpie's own trigger to draw you through your entire deck.