4. Botfly
The human botfly (Dermatobia hominis) is a small fly that looks like a bumblebee. What’s so scary about it? Try having a maggot pop out of your skin after it has nestled there for quite some time. Native to Central and South America, it has been known to nest in humans. Even though the fly itself will not bring any infections or pathogens, it will infest the skin of mammals and live out the larval stage in the subcutaneous layer, causing painful pustules that secrete fluids.
The burrowing of larvae in the skin cause a raised lesion that becomes hard and sometimes painful. In some cases, human victims can feel the larvae moving when they shower or cover the wound. The victim’s body reacts with elevated white cell counts thus the secretion of pus.
Graphic enough for you? We’ll draw the line here. Just imagining having a moving maggot under your skin is enough to make anyone sick.