Bloodmist Infiltrator

A 3/1 is a stat line that begs to attack and dreads a chump block: fragile enough that one blocker trades cleanly, aggressive enough that its damage matters. The attack trigger resolves that friction by converting a spare body into unblockability, which is the point where this card stops being a beatstick and becomes a delivery mechanism. Sacrifice fodder goes in, three unblockable damage comes out, and the same trigger feeds every death-matters payload you happen to be running: aristocrat drains, undying and persist bodies you want to recycle, tokens you were going to lose in combat anyway. The design sits at the intersection of two black staples that rarely share a card, evasion and a sacrifice outlet, and it charges you a creature per turn to keep both. The tension is real, because unlike a free sacrifice outlet this one only fires on the attack step, so the fodder you feed it has to be worth more dead-and-swinging than alive-and-blocking. That combat-locked window (it triggers only when this creature attacks) is what keeps it from being a repeatable combo enabler; you cannot sacrifice on demand at instant speed, only once per swing, and only if this creature is the one attacking. What you are left with is a recurring engine that pushes damage and empties the board in the same motion, which is exactly the shape sacrifice decks want.