"Mick" is a mantid-esque bug of a mostly unknown type that has a disturbing quality. Its species reproduces through the bizarre ability to inseminate hosts with its proboscis. As it sucks its host's blood, it can alter the victim's DNA to make them suitable for carrying and birthing its young. In the story, Mick is the only one seen although later information implies that there are more of its kind.
At the start of Sick Girl, Ida Teeter receives a package containing the bug which she affectionately nicknames "Mick". As she becomes closer to Misty Falls, "Mick" escapes from its tank and hides within a pillow. It later kills and eats the landlady's dog. While Misty becomes Ida's lover, "Mick" selects her as a host and starts the insemination via inserting its proboscus into her ear. Unfortunately, this sets off the chain of events that leads to Misty's transformation into a monstrous bug-human hybrid and leads to the deaths of the landlady and Ida's colleague Max. At the end, "Mick" initiates the insemination process on Ida and is last seen continuing to do so which will likely result the deaths of the two women.