Sting of Death

Egon is the mildly disfigured assistant to Dr. Richardson who secretly loves Karen. He engineers a transformation device that turns him into a half-man, half-jellyfish monster to seize control. His killer spree targets the women at the house and party, driven by a dangerous blend of love and rage. He is fatally injured by John Hoyt during the climactic confrontation as the lab's machinery explodes.

Karen is Dr. Richardson's daughter and the object of Egon's affection, though she becomes involved with John Hoyt. She is drawn into the danger surrounding Egon's experiments and is forced to confront the monster's reach. Karen's survival hinges on John's intervention and the lab's collapse. Her resilience is tested as she navigates love, danger, and a desperate escape.

John Hoyt is Dr. Richardson's assistant and Karen's love interest. He becomes the pragmatic protector who confronts Egon and fights to rescue Karen. In the final confrontation, Hoyt fatally injures Egon and helps Karen escape as the laboratory explodes. He embodies rational, action-driven heroism in the face of monstrous science.

Dr. Richardson is a marine biologist studying the evolution of sea life and the host of the group at his home. He oversees the scientific experiments that blur the line between science and danger. His role anchors the night’s social gathering and the subsequent catastrophe tied to his lab's ambitions.

Louise is one of the college friends staying at the house. She participates in the pool party and becomes entangled in the escalating terror as the monster's rampage begins. Louise's arc is short, serving as one of the early victims that signals the danger lurking beneath the surface.

Jessica is part of the group of friends at the Richardson residence. She is involved in the search for Donna and becomes one of the victims of Egon's murderous spree. Jessica's arc contributes to the escalating tension and fear as the group grapples with the monster.

Donna is another member of the college group who participates in the party and falls prey to the monster's attack during the pursuit through a swamp. Her fate adds to the sense of danger and the film's body count. Donna's role underscores the peril faced by the young women in the story.

Susan is part of the group of friends staying at the house and is killed during the sequence of murders. Her character helps illustrate the widening impact of Egon's rampage beyond the initial targets. Susan's demise reinforces the peril and urgency that culminate in the final confrontation.