Galileo

Galileo is Madame Curie's cousin, he lives in a kitchen cupboard in a house on the other side of town. He has invented various gadgets and machines which Aristotle is jealous of. He often sends them to Madame Curie, which infuriates Aristotle.

Trivia

 * He is named after Italian physicist, Galileo Galilei.
 * Despite never physically appearing, he is frequently mentioned in various episodes.