Mikaeus, the Unhallowed + Bloodflow Connoisseur + Thunderblust

Mikaeus, the Unhallowed

Bloodflow Connoisseur

Thunderblust

How it works

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