You scream, you expand, you explode.
I know what you're asking: what more could you ask for in a horror film starring Peter Fonda, right?
Its best to think of Spasms (1983) like a What If? Scanners (1981) met Anaconda (1997), an interesting concept that (unfortunately) is unfulfilled by the time the credits roll. Though the tagline of the the film promises plenty of gooey head explosions, its plot actually follows a giant snake/serpent that attacks people with its deadly venom (which in turn induces the 'splosions). Oh yeah, and the snake is somehow psychically linked to our hero Jason (actor Oliver Reed) and some sort of odd serpent cult.
Having become notorious for garnering negative reviews from genre fans and films critics alike, the movie's biggest flaws are due in part to some shortcut creature effects, unresolved subplots and a flaccid climax that will leave you in a "WTF?" daze. The death scenes are all pretty entertaining and, while there's sadly little in terms of expanding or exploding human beings, snippets of gratuitous nudity do abound. So... its not a total loss, right?