The bo'tous spore was a biological weapon developed by the Yuuzhan Vong. It was housed in the lungs of a host, who could then exhale the spores in the presence of an intended target. Upon contact with open air, the spores would become bo'tous. A skilled user could carry four doses of bo'tous spore. The only documented use of bo'tous spores was in 25 ABY when the priestess Elan attempted to assassinate several Jedi by feigning defection to the New Republic.