Tiny, shapeless invaders can find their way from ponds to the human brain and cause an infection so severe that it has a 95% fatality rate. The amoeba Naegleria fowleri naturally lives in ponds, feasting on bacteria, but once it enters the human body, it makes a run for the brain tissue, traversing complex, tight spaces to reach its destination.

A recent study set out to crack the secret of how a tiny amoeba steers itself through unfamiliar terrain without any guide.

Researchers built a microscopic obstacle course for the amoebas and filmed their every move, tracking how they squeeze through tight spaces and tackle different environments. They identified a few core mechanisms behind their navigational success. First, a love for tight spaces.