They're dealing with the unknown. The unknown must be destroyed

A cop on the track of a criminal finds himself in the midst of an unfinished subway tunnel, when his flashlight reveals a startling discovery: a three meter long scorpion-like Bug. With one slice of its massive tail the bug fells the man and devours him. FBI agent Matt Pollack is brought in to investigate, and when forensics reveal the source of the problem, he turns to his friend and entomologist Emily Foster for help.