The Shadowbeasts are the terror of anywhere man has made the city. With the advent of the Metropolis, the Shadowbeasts numbers swelled rapidly, like humanity's did with the advent of farming. The Shadowbeasts used to live in the humid jungles of the Amazon, until a team of explorers found them, and brought a couple of eggs back home, for study. To make a long story short, the Shadowbeasts (so named for how they can, all to easily, block out the sun) escaped the lab, and have since spread to cover anywhere with large cities. This includes North America, Europe, North Africa, and East Asia (such as China and Japan), among other areas.
Description: The Shadowbeasts look like giant locusts, each roughly 10-15 feet long. The picture below is a locust.
The difference between an actual locusts and a Shadowbeast (besides size) is that the Shadowbeast has an additional pair of legs, located in their midsection. This extra pair is designed to grab onto things, with each of these legs ending in three hook-like "fingers." Other than that, the Shadowbeast is a dark green in color, with dark gray wings. This coloring pattern allows them to be camouflaged in the dark.
Behavior: During the autumn, winter, and spring, the Shadowbeasts generally live alone, separate from the Swarm. But during the summer, the Shadowbeast go into what is known as their Gregarious phase. A phase almost exactly like that of the locust. During this Gregarious phase, nearby Shadowbeasts band together and form Swarms. The swarm generally contains 5000-10000 Shadowbeasts, but some have been reported to be close to a million. The Swarms, once formed, will make a nest. This nest will be, essentially, a giant cage for its prey (read humans). The nests will always be in secluded areas, and will be hard to reach from the ground. The nests will also be guarded by workers. These workers are only five foot long, and stay within a 20 mile radius of the nest. They will also care for the humans by providing them with food and water, and will also make sure they stay in the nest. Once the nest is complete, the main swarm will wander around, looking for a city, traveling until they find a city. They will generally leave towns and villages alone (like a fisherman would leave a baby fish, so that the baby fish can grow into a big fish). Once a city is found, they will attack. Like in the description, they will carry off people into the air. Once in the air, the Shadowbeast will eat its victim, and dive down for more. The swarm, once each member is satisfied, will carry the remainder of humans back to its nest for later. One Shadowbeast can carry two or four humans (depends on how big the "grabbing" legs are. Some are big enough to carry two in each leg, others one). Once the humans are in the nest, they will seek out another city. Towards the end of summer, they will have a large collection of humans. From late summer, to early autumn, they will mate, and lay their eggs inside the nest. They will proceed to cover the nest, forming a dome over it. By winter, the eggs will break, and the larva will emerge. Throughout winter, the larvae will feast on the humans inside the dome and grow. By summer, the larvae will be fully grown.
Diet: Humans, though workers will east other large mammals (like deer, moose, etc)
Movement Rate: can sustain a speed of 40 mph for days. Top speed is 80 mph, but can only do such a speed for a short time.
Life Span: 5-10 years
Natural Defenses: Camouflage during night, thick exoskeleton (bulletproof), mobility
Weaknesses: Exoskeleton armor can stop bullets, but not much bigger than that. A direct hit from a tank will take one down easily. Also, explosives are useful against them, as long as they have a timer or something else that makes them explode in the swarm (and not after they hit an individual Shadowbeast). And if enough of them are killed (around 50-75% of them) they will disperse and look for another swarm.