Jackie Twu (Sometimes misspelt as Jackie 2) is the son of Jackie Chu. He first appears in The Fly Problem!. He's 2 years old and he has 2 PHD's in Calculus! Jackie Twu was voiced by Chilly in The Fly Problem! Then he was later voiced by Chris in later episodes.
Unlike Jackie Chu, Jackie Twu does not have slant eyes Because according to Jackie Chu, he doesn't go into puberty until he's 13 years old.