cannonball jellyfish

:  a nearly globular, scyphozoan jellyfish (Stomolophus meleagris) of warm waters that has a greatly reduced mouth, short oral arms, and no tentacles and that often occurs in swarms many miles in extent But cannonball jellyfish don't sting unless they're picked up. The long-strand tentacled jellyfish also known as sea nettles and Portuguese man of war are much more dangerous and menacing … — Drew Dixon, Florida Times-Union (Jacksonville), 21 Apr. 2011 Fishing boats from beleaguered Gulf Coast towns could be on the water by next month trawling for cannonball jellyfish, a fist-sized mass of fiber that's inspiring dreams of wealth. Officials see jellyfish as a product ready for export to Asia, where it is popular in Chinese, Thai and Korean cooking. — John Kennedy, Orlando Sentinel, 15 July 1996 —called also cabbagehead jellyfish, jellyball