Farnsworth's grandmother

Farnsworth's Grandmother is an unseen character who has been mentioned various times throughout the series. It's unlikely that she was a scientist, because the Professor doesn't speak of her when he's telling Fry about the great minds that have inspired him all his life in "The Duh-Vinci Code". Nevertheless, it's possible that she was a role model to her grandson, as some of "his inventions" actually belonged to her.

Trivia

 * She's probably deceased, considering the Professor is 165 years old.

Quotes
Farnsworth: Bender, be careful. That's the ship's diamond filament tether. It's unbreakable. Bender: Then why do I have to be careful? Farnsworth: It belonged to my grandmother.