Dr. Ethan Dooku is the main antagonist from the episode "Return of the Scientist". He is a evil robotic scientist only appears in a one episode. At the end of the episode, he was killed by Jessie's father. He was voiced by Alice Cooper.
- He is crazy, sneaky and frightening.
- He is very slender, light skin, robotic arm, robotic leg and robotic face, grey messy hair, green eyes, large teeth and wears white lab coat, black shirt, necktie, goggles with purple and green lens, black pants and shoes.
- His last name is similar to the Count Dooku from Star Wars.