The Venture Bros Season 1 Episode 13 - Return to Spider-Skull Island Episode Title:Return to Spider-Skull Island.Episode Description:Dr. Venture has surgery to remove a tumor from his abdomen. Thinking that their father is pregnant, Hank and Dean run away from home and wind up in a Scared Straight!-style prison program led by The Monarch. The "tumor" turns out to be Dr. Venture's twin brother, who has been living inside him since being devoured while the two were still in the womb. The twin attempts to claim his birthright by killing Dr. Venture, but is stopped by Brock and H.E.L.P.eR. After a truce, he takes the name Jonas Venture Junior and Dr. Venture gives him the X-2 and their father's facility on Spider-Skull Island. The family recovers Hank and Dean, but they are accidentally killed by Monarch Henchmen 21 and 24.