Bobbin

A bobbin is an object that is the main focus of the episode "What is that Thing?" It belongs to Mr. Ratburn, who uses it in a play about the history of the sewing machine.

Arthur and his friends have their own ideas of what the bobbin is used for until they learn its real purpose:
 * Arthur imagines it as a yo-yo for leprechauns and a robot's brain.
 * Brain thinks that the bobbin is a wheel from someone else's model plane, and puts it on his.
 * Francine uses it has a "cat hypnotizer" to convince Nemo that he likes water.
 * Muffy calls it a "doll rescue rope" after she uses it to rescue her Arnie doll from a sewer grate.