Stewie Griffin: The Untold Story! 2005

Stewie, the maniacal baby genius, is distracted from his plans for world domination when he sees a man who looks just like him on television. Convinced that this man must be his real father (after all, how could he possibly share genetic material with the dimwitted Peter?), Stewie sets off on a cross-country road trip to find him. But his incredible journey leads him to discoveries far more vile and shocking than anything found in his diaper.