Mikaeus, the Unhallowed + Soulstinger + Bloodflow Connoisseur

Mikaeus, the Unhallowed

Soulstinger

Bloodflow Connoisseur

How it works

1. Activate Bloodflow Connoisseur by sacrificing Soulstinger.
2. When Soulstinger dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
3. When Soulstinger enters the battlefield, it triggers, putting a -1/-1 counter on it.
4. Resolve the Bloodflow Connoisseur ability
5. Repeat.

This clever loop is held together by Mikaeus, the Unhallowed, whose static anthem grants undying to all of your non-Human creatures while naturally boosting their stats. When you feed Soulstinger to Bloodflow Connoisseur, Mikaeus's granted undying brings Soulstinger right back to the battlefield with a +1/+1 counter. Simultaneously, Soulstinger's own enter-the-battlefield trigger places two -1/-1 counters on itself; state-based actions immediately cause the +1/+1 counter and a -1/-1 counter to annihilate each other, leaving Soulstinger with no counters and primed to repeat the entire sacrifice cycle all over again.