A group of college kids travel south to Florida on spring break with their friend Karen, whose father, Dr. Richardson, is a marine biologist currently studying jellyfish. The kids, Louise, Jessica, Donna, Susan and Karen, stay with a man named Dr. John Hoyt. The kids insult and ridicule Dr. Richardson's assistant, Egon, who is in love with Karen. Egon creates a murderous jellyfish mutant which begins to go on a killing spree.