In the tradition of the classic "chicken or the egg" debate, one wonders what came first: the title for Black Sheep, or the story? It hardly matters, because this film's New Zealand production team got it right, correctly gauging the humor value of watching these normally harmless creatures tear the flesh of their human keepers. Black Sheep is certainly more comedy than horror -- think the scene in Monty Python and the Holy Grail where the bunny slaughters King Arthur's knights -- but it's got gruesome enough visual effects to please the Troma crowd as well. What keeps it from becoming a classic horror comedy is that it doesn't quite build on the central concept. Black Sheep is one of those rare films whose appeal is instantly communicated through a one-sentence description, prompting laughter from most of those who hear it. The challenge, then, is to take the movie places that the concept alone can't, and Black Sheep doesn't quite do that. Still, there's much to recommend in a film that also functions as a parody of/homage to zombie and vampire movies, featuring bitten victims who slowly transform into human-sheep hybrids. The fact that the lamb rampage results from a particularly brutal form of animal testing means it's also likely to win fans among People for the Ethical Treatment of Animals. At the same time, Jonathan King's film is layered enough to skewer those same people, as a lab sample stolen by self-important guerrilla activists is responsible for the initial outbreak of mayhem. By always keeping its tone light, Black Sheep is never less than a pleasing diversion.