Miss Spider is a heroine from James and the Giant Peach. She is James' first friend since he had to live with his mother's mean sisters, Spiker and Sponge. She is a loner, but later warms up to James, especially because of his kindness to her first. Both her speaking and singing voices were done by Susan Sarandon.
Miss Spider is first seen as a normal-sized spider in James' window. James tells her she probably shouldn't build her web there because his aunts might see her and they hate spiders. Through a song, he introduces himself to her. The next morning, when his aunts do see her, he saves her from them.
Later, she is seen again, this time, much bigger, in stop-motion form (this being because she was an inhabitant of the peach, and as the "crocodile tongues" got into the peach and into them, the peach and bugs all got bigger). She explains the boy's name to the other bugs. (James is now in stop-motion mode)
One night, while Miss Spider is building a web with James in the middle, she reveals that she prefers to be alone, and it is her nature for people to fear her, thus, she cannot change. When James tells her she is very kind to him, she tells him that perhaps it's because he was kind to her first. This reveals that Miss Spider and the spider in James' window are the same spider. She is wrapping James up in silk as a blanket. She then tells him nobody can make him do anything if he doesn't let them. And then she puts a leaf over him and kisses him goodnight.
In a cold place, she and James both team up to rescue an abducted Mr. Centipede (who shares his feelings with Miss Spider), but they don't manage.
Later, at last in New York, though James goes back to live-action mode, the bugs stay in stop-motion. As James stands up to his aunts, Miss Spider then wraps them up before they are arrested.
And finally, the peach stone is made into a giant house in Central Park. In the end credits, Miss Spider has a club.
When Miss Spider is first seen as a normal-sized spider, she is played by an actual spider. When Paul Terry, who had played James, was playing in that scene, the spider bit his hand, which is why he never acted again.