Night Revelers

The conditional haste here is a flavor mechanic doing real strategic work: a vampire mob that charges only when there are humans to terrorize. Mechanically, the 4/4 body comes down swinging precisely against decks built around Human tribal aggro and goes inert against everyone else, a built-in tribal-warfare clause that rewards the very matchup it was designed to punish. The clever part is that the static ability reads the opposing board rather than your own deck: you do not control whether the vampires arrive ready to attack, your opponent does, by whatever creatures they happen to be running. Against a control shell or a non-Human tribe, this is a plain 4/4 that has to sit a turn before swinging, fairly priced for its era and nothing more. Against a deck flooding the board with Humans, it lands ready to race them, turning the opponent's gameplan into the condition that switches on the answer. Tempo dictated by the opposition is the entire point: sharpest exactly when the opponent is most committed to the tribe it hates. It sits in a small line of designs that key off enemy creature types rather than friendly ones, where the payoff is contextual and the worst case is still a serviceable beater. Plain when unopposed, pointed when provoked.