At first, Dirk is happy with his job and even enamored with the doctor's nerdy daughter, but then things take a dark turn when the doctor starts giving him injections (under the false pretense that they will help build up his immunity to snake poison), but in fact, he's pumping poor Dirk up with some experimental bullshit that slowly turns him into a sssssssnake! The slow behavioral transformation and eventual physical transformation was fun to watch, but I had a hard time believing that Dirk's character was so oblivious to what was happening.
The story sounds ssssssstupid and it kinda is, but Strother Martin's performance is truly disturbing and he easily carries the film into Worth Watching territory. I do wish the movie had been just a little more risque though. Example: the leaves covering up the skinny dipper's nudity. This is a horror movie, if you're too goddamn chicken to show a sexy naked butt cheek then the audience knows there's not going to be any violence worth a damn on the horizon. Oh well, that's my main gripe.
Overall, the movie was better than I expected and I'd watch it again, but just remember this is an early 70's studio-backed "horror" movie, so don't expect anything too outrageousssssss.
Somebody should make a sequel to this film and give it 14 s' instead of 7. SSSSSSSSSSSSSS.
I like how in the description section of this ad, they misspell the title of the film.