Centaur's Herald

A green one-drop that pays out a 3/3 only if you spend three more mana to kill it: the body is a placeholder, a 0/1 wall that exists to hold the activated ability until you can afford it. Total investment for the Centaur is four mana split across two turns, which is the constraint that keeps the trade fair: you front a one-drop early, then cash it in later for a body that comfortably beats most two- and three-drops in combat. The design splits a creature into a deferred payment, letting a slow deck land something cheap on turn one without committing the full cost, then convert it on a turn when mana would otherwise sit idle. The sacrifice clause does quiet work beyond the rate, too: it turns the Herald into a creature that wants to die, feeding anything that rewards a graveyard or a death trigger, and the token it leaves behind is a fresh permanent rather than a transformed one. What it offers is flexibility bought with patience, smearing a single creature's cost across the curve and asking the deck to value board presence on an empty turn one over raw efficiency.