Mikaeus, the Unhallowed + Viscera Seer + River Kelpie

Mikaeus, the Unhallowed

Viscera Seer

River Kelpie

How it works

1. Activate Viscera Seer 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. When River Kelpie enters, its first ability triggers, causing you to draw a card.
4. Resolve the Viscera Seer ability.
5. Activate Viscera Seer by sacrificing River Kelpie.
6. When River Kelpie dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
7. When River Kelpie enters, its first ability triggers, causing you to draw a card.
8. Resolve the Viscera Seer ability.
9. Repeat.

This crafty loop relies on a brilliant counters-cancellation trick powered by Mikaeus, the Unhallowed, whose static ability grants undying to your non-Human creatures. By sacrificing River Kelpie to Viscera Seer, the Kelpie alternatively returns via persist with a -1/-1 counter or via undying with a +1/+1 counter; these opposing counters instantly cancel each other out upon entering the battlefield, resetting the creature's slate entirely. Because River Kelpie enters the battlefield from the graveyard each time, its own triggered ability fires relentlessly to draw you your entire deck through the sacrifice outlet.