Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
"Where Everything Seems Possible and Nothing Is What It Seems."
This is a cult classic coming-of-age children's movie influenced by Alice in Wonderland, M. C. Escher's prints, Maurice Sendak's Where the Wild Things Are plus lots of director Jim Henson's crazy Muppet creatures. It's about a spoiled teen named Sarah (14-year-old Jennifer Connelly) who is forced to grow up by becoming the hero in an adventurous journey to save her baby brother.
Sarah is upset that she is forced to baby sit her baby brother Toby, and when he won't stop crying, she gets angry and calls on the Goblins to come and take him away. After the little muppet Goblins come and take him, Sarah immediately regrets it and demands him back from Jareth, the Goblin King (David Bowie, with the world's worst rock star haircut, scary eye make-up and an even more frightening codpiece. Bowie also wrote and sings 5 songs for the movie.)
Jareth tells Sarah to go play with her toys and her costumes and forget about the baby. Then he holds a magic crystal ball in his hand and we watch it turn into a snake. He stretches the snake out between his hands held in front of himself, then tosses it around Sarah's neck. (People in movies often do this with snakes, but I'll bet that if you really did throw a snake it would be very hard to get the snake to wrap around someone's neck. You could hurt or kill the snake, so don't do it.) Sarah panics for a minute until the snake turns into a scarf. She refuses to forget about Toby so Jareth gives her until the 13th hour to rescue him from the Goblin castle (where the clocks go to 13.) Sarah then goes into the labyrinth to try to find her way to the castle to rescue her brother.
Connelly holds a fake snake around her neck. Bowie holds a live one. I'm not sure what kind, but my best guess is that it's a banded water snake, Nerodia fasciata. Some of them have red bands inbetween the black and checkered bellies as we see here. There's a Reddit thread asking what it is, with some people agreeing with the banded watersnake ID. If that's what it is, it's a very small one. It's strange they would use a watersnake since they don't take well to handling and like to expell all of their stinking fluids through their cloaca when they're upset.