Sssssss (released as Ssssnake in the United Kingdom and Japan) is a 1973 American horror film starring Strother Martin, Dirk Benedict and Heather Menzies. It was directed by Bernard L. Kowalski and written by Hal Dresner and Daniel C. Striepeke, the latter of whom also produced the film. The make-up effects were created by John Chambers and Nick Marcellino. It received a nomination for the Best Science Fiction Film award of the Academy of Science Fiction, Fantasy & Horror Films in 1975.
Dr. Carl Stoner, a herpetologist, sells a mysterious creature in a crate to a carnival owner. He later hires college student David Blake as an assistant, claiming that his previous assistant had left town to attend to a sick relative. Unbeknownst to David or anyone else, Stoner is a delusional man, convinced that humanity is doomed and is attempting to prepare for what he believes to be the inevitable by working out a method of transforming humans into reptiles that can survive any ecological disaster that would wipe out humanity.
Stoner begins David on a course of injections, purportedly as a safeguard against being bitten by a snake in his lab. David's skin slowly starts to change and even peel like a snakeskin. He begins to have strange nightmares and goes into a coma when having dinner with Stoner, not waking up until a few days later. He also begins to lose weight, but Stoner tells him those are side effects from the venom. David begins a romance with Stoner's daughter Kristina, although her father objects and insists that she not have any sexual relations with him.
When David wakes up the next morning, he looks in the mirror and screams in horror. Later, a distraught David is in the lab, where Stoner gives him another injection. Meanwhile, Stoner's suspicious colleague, Dr. Daniels, arrives to inspect the property. Stoner attempts to hide David in a corner, but David gets enough strength to walk to a window, allowing Daniels to see that his face has become green and scaly. Before Daniels can react, Stoner knocks him out and feeds him to a python, and David collapses.
Kristina visits a carnival freak show and is horrified when she sees a bizarre "snake-man", whom she recognizes as Stoner's previous assistant. Distraught, she races back home to save David, who is currently mutating into a king cobra, brought about by Stoner's injections. Stoner is bitten by a real king cobra from his lab and dies, just as David's transformation is complete. Kristina arrives home and finds her father's body with the real cobra next to him. Growing suspicious, the police arrive and shoot the cobra before heading to the lab where a mongoose is attacking David's neck, attempting to kill him. But the police do not have a clear shot, and as Kristina screams David's name, the movie ends abruptly, leaving their fates uncertain.