Invader Zim is taking over the world and all its inhabitants. Yes, Nickelodeon is back on February 22, 2011, with Invader Zim: Operation Doom DVD set. This set is packed with 13 exciting episodes of America’s favorite cult TV show. Join Zim and his wacky friends as they go on outrageous adventures. The collection is filled with top rated episodes like; Career Day, Battle Dib, The Nightmare Begins, Mysterious Mysteries and many more. You will soon see why this is…