According to Lee Kalcheim, the original script for the film was far different from the completed film. Hired by producer Charles B. Moss, Kalcheim's original screenplay, entitled It Drinks Hippie Blood, followed a group of hippies camping on a cove who are attacked by a creature that lives in the water. Kalcheim described his screenplay as a satire: "John turned-the-screw so to speak making it a serious, darker theme. The simplicity of the film worked perfectly to create a scary mood."