scleroderma citrinum: an earthball fungus that is a dingy brownish yellow and a dark purplish interior; the peridium is covered with a pattern of small warts
earthball: any of various fungi of the genus Scleroderma having hard-skinned subterranean fruiting bodies resembling truffles
yersinia pestis: a bacillus bacterium that causes the plague; aerosolized bacteria can be used as a bioweapon