Tracker

Trackers are powerful, highly resilient and durable creatures that scour the earth for human survivors. When they find some, they call reinforcements to neutralize them. Trackers are genetically modified creatures who combine many abilities of many earth animals. For example they can produce spider web from their mouths, which they use to web useful things and carry them back, they have three sets of wings that make flying easy, and last but not least their claws are powerful as well. The front of their body is also covered in thick shells, making them also hard to hit with bullets. On their heads, they have two eyes that can monitor the entire surrounding area, which makes them their weak spot. The trackers have four legs, covered in small and bigger claws, that allow them to climb walls and most surfaces.
Their wings are also very big, the scientists attribute this to their homeplanet's air density. They say the atmosphere is ore dense, and as a result there is more gravity. Therefore, their bodies are stronger and the wings needed to fly are bigger, that's why they fly very well on earth. He also says that in their hometown there must be much more oxygen in the atmosphere, becaus eof their big size.