Naegleria fowleri amoebas, like these, can glom onto nerve endings in the nose of an exposed individual and motor along them into the brain. There they can trigger encephalitis, a nerve infection that is quickly lethal. Feeding cups on their surface are where they take in bacteria from the environment or bits of tissue while living within a human host. Credit: F. Marciano-Cabral/Va. Commonwealth Univ. Sch. of Med.