Botfly (of family Oestridae)
A stout-bodied, dipteran fly that is highly variegated and is often found in Central and South America. Botfly comes in different species and each species is adapted to attack a specific living being. Different species are given different but funny names such as Sheep Nose Botfly, Horse Stomach Botfly, Human Botfly, etc. Seems like they are named after their prey and the organs which they target. Does Horse Stomach Botfly like to attack the stomach of a horse? Beats me but that is somehow a fact!
What is so scary about botflies, if you ask? Well, their larvae, in the form of half-inch and bulky maggots, love to dwell in and feed on the living flesh and organs of other living beings. For example, Horse Stomach botflies lay their eggs in the grass only to be consumed by a horse later. With the eggs hatched in the horse’s mouth as a result of the bodily heat, the larvae of botflies chew through the tongue of the horse and burrow their way into its stomach and begin to grow. Once they are fully grown, they will come out from the anus of the horse … I mean … they will hide themselves in the excrement to be discharged by the horse.
The Human Botflies can attack basically any part of a human body in an indirect and later direct manner (what am I saying?). Well, a Human Botfly first lays its eggs on a mosquito or horsefly, which later lands on a human and subsequently drops the eggs onto the human skin. The human’s body heat will hatch the eggs and the larvae will then screw themselves into the human flesh and begin to live under the skin! There are few movies with the same title “Under the Skin” but none of them have happy endings. The Human Botflies can attack any part of the human body, depending on where the eggs land on the human! They can crawl into your brain, eating your thoughts, and they can even come out from your tear ducts.
Reference: http://www.cracked.com/article_15816_the-5-most-horrifying-bugs-in-world.html