Micrathena gracilis is a spider in the family Araneidae (orb-weavers), commonly known as the spined micrathena. This spider spins a moderately large (can be 30 cm (11.81 in) or more across), very tightly coiled web, often in wooded or brushy areas. Some call it the "CD spider" because its webs can make it appear as though there are compact discs hanging from the trees. It is completely harmless to humans.