Jellyfish Swarms Screensaver - Version 1.2 The free screensaver Jellyfish Swarms was created by RateMyScreensaver.com and contains 22 high resolution images of Jellyfish. A group of jellyfish is often called a smack. Many species of jellyfish are also capable of congregating into large swarms or blooms consisting of hundreds or even thousands of individuals. The formation of these blooms is a complex process that depends on ocean currents, nutrients, temperature and oxygen content.