Mikaeus, the Unhallowed + River Kelpie + Bloodflow Connoisseur

Mikaeus, the Unhallowed

River Kelpie

Bloodflow Connoisseur

How it works

1. Activate Bloodflow Connoisseur 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 Bloodflow Connoisseur ability.
5. Activate Bloodflow Connoisseur 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 Bloodflow Connoisseur ability.
9. Repeat.

This clever loop exploits the opposing mechanics of persist and undying to achieve immortality for River Kelpie. Because Mikaeus, the Unhallowed grants undying to your non-Human creatures, River Kelpie alternates between returning with a -1/-1 counter from persist and a +1/+1 counter from undying, which constantly cancel each other out and reset its ability to die again. Meanwhile, Bloodflow Connoisseur provides the necessary sacrifice outlet to keep the cycle moving, while River Kelpie's own trigger rewards every single return from the graveyard by letting you draw your entire deck.