And then there's Sting, the Goblin King himself, looking evil in the tight leather pants he'd wear as he went on to fame in the World Wrestling Federation years later. This one depends on your take on the story too. If this is real, then Sarah's up against the power of a wizard and his magical labyrinth. Obviously, the film is played pretty fast and loose, taking on a much lighter tone than the oft-compared Dark Crystal . But you don't have to have singing kings and silly goblins if you don't feel it would fit into your campaign setting.
Time is of the essence, even if it does tend to change once in a while.
The characters don't have forever to get through the labyrinth before them, and if they miss their deadline, then something bad will happen. That's up to you. Or perhaps it's simply a younger sibling, or even the son or daughter, of one of the characters. Whoever it is, they can't help themselves, and they're depending on the characters to save them. This one's definitely a one-nighter, unless you're being sadistic and want to trap the characters in a maze for an extended period of time.