Nekrataal

Stapling a removal spell to a body is one of black's oldest design tricks, but this is the version that defined the rate: a first striker that kills a creature the moment it lands, with the regeneration shut off so the kill is clean. The targeting restrictions are the design discipline doing the balancing work: it can't touch artifacts or black creatures, leaving mirror-match opponents and artifact decks a lane around it and stopping short of a universal answer. What it really sold was the structural idea that a creature could be a two-for-one without any extra effort: cast it, get a kill, keep a body that can block or attack into a profitable trade thanks to first strike. Wizards has reworked this exact shape across colors and eras (Flametongue Kavu took the model to red, Shriekmaw gave black an evoke version with the same nonartifact, nonblack clause copied nearly word for word), and the design vocabulary for "creature that kills on the way in" still treats this as the reference point. The body is fragile and the four mana is honest, but the line it draws between tempo and card advantage is the one every value creature since has had to answer to.