Overview: A war has been going on for billions of years that breeds well armed monsters who struggle with other monsters for survival. Having no particular interest in us, most of them are relatively harmless, as our immune systems deal with their weapons handily. But there are exceptions. Naegleria fowleri is an amoeba that not only has developed a deadly taste for human brains but is also a match for our defenses and a guest in dramatic headlines. What happens when this monster enters your body?