Among the monsters said to roam the world's jungles and desolate deserts, none is more feared than the chupacabra---the blood-sucking beast blamed for the mysterious deaths of thousands of animals since the 1990s. To some it is a joke; to many it is a very real threat and even a harbinger of the apocalypse. Originating in Latin America yet known worldwide, the chupacabra is a contradictory and bizarre blend of vampire and shapeshifter, changing its...