A group of college students travel south to Florida on spring break with their friend Karen (Valerie Hawkins), whose father, Dr. Richardson, is a marine biologist currently studying jellyfish. At the party, Karen's friends insult and ridicule Dr. Richardson's assistant, Egon, who is in love with Karen. Egon creates a murderous jellyfish mutant which begins a killing spree and eventually brings Karen to his secret laboratory in the swamp.