Naegleria fowleri is a terrifying little critter, an amoeba that goes straight for the brain upon its infection of its host. It is also known as the brain-eating amoeba, and it feasts on bacteria. Even scarier, it lives in water and can travel up through the nose and into the brain, where it does its damage, usually ultimately killing a person. A simple trip to the lake or even contact with water from around your dwelling can expose you to this parasite.
The initial symptoms of this tiny beast begin anywhere between one and nine days after exposure, usually starting at about five days, and can include headache, nausea, vomiting, and basic flu-like symptoms at first. But then in can develop into a lack of attention to people and surroundings, as well as vertigo or loss of balance, hallucinations, and eventually death.