Nobody likes being annoyed by the constant buzzing of a house fly, but at least it’s not as bad as having a screw worm fly plant eggs into your skin that will eventually develop into ravenous flesh-eating maggots. This particular description may sound like horror-fiction, but despite their small size, not all flies are as harmless as the ones you spot within your house each summer. In fact, some flies are real jerks! And the screw worm fly fits the bill.

This fly used to exist within the United States until it was eradicated several decades ago, unless you count the swarm of screw worm flies that attacked Florida beachgoers two years ago. Screw worm flies lay between 250 and 500 eggs within exposed animal flesh, including human flesh. Most of the time, screw worm flies lay their eggs within open wounds, but in some cases, they will lay their eggs within a person’s ear canal or up his/her nose. These hundreds of eggs develop into hungry maggots that feed on flesh and tissue. These infections can cause severe tissue damage and even death, such as in one case where a screw worm fly laid eggs up a sleeping man’s nose. Once doctors learned that this man had maggots eating away at the organs within his head, it was too late to save his life. This may be the only recorded case of a person literally being eaten alive by insects, in this case maggots.

In 1883, a man began experiencing what felt like a severe head cold, but little did he know, this “head cold” was only the first symptom of a far more serious medical condition. A screw worm fly planted eggs within the man’s nose while he was sleeping. The maggots that emerged from the eggs began feeding on the tissues within the man’s nose and head before moving on to the soft palate. The damage inflicted to the man’s soft palate caused him to have speech problems and he developed symptoms of delirium before losing his mental faculties entirely. After removing 250 maggots from the man’s head, doctors thought that he may recover, but the maggots had already progressed to feeding on the Eustachian tubes within his ears. Shortly after the maggots were removed, the man died.

Did you know that there existed a fly species that could inflict this kind of damage onto a human?