Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
Members of a secret government agency force a psychic, Alex (Dennis Quaid), to help them experiment with sending psychics into other people's dreams in order to help them cure the U.S. President who has nightmares about nuclear war. When Alex gets into the dream of a young boy troubled with terrible nightmares, he discovers that the source of the nightmares is a creature the boy calls The Snakeman. He's not really a snake, since he has arms and legs, but he does have the hooded head of a cobra and fangs, and the name, of course, so I'm including him here.
This was made in 1984 so the effects are pre-computer graphics and they're very cheezy. He looks like he is made of rubber because he probably is. The Snakeman shows up again in a second dream when another psychic, Tommy (David Patrick Kelly), who has learned how to kill people in their dreams, turns himself into Snakeman based on a drawing that Alex made of the monster in order to scare Alex who is in the same dream. We see him transform into the Snakeman with old-style progressive animated-type effects. Then the Snakeman shows up again in a third dream when Alex turns himself into a different-looking version to scare someone else to death.