HOLY SH!T! - Hercules is an English Mastiff and who has a 38 inch neck and weighs 282 pounds. He was recently awarded the honorable distinction of Worlds Biggest Dog by Guinness World Records. The three-year-old is far larger and heavier than his breed’s standard 200lb. limit. Hercules owner Mr. Flynn says that Hercules weight is natural and not induced by a bizarre diet: “I fed him normal food and he just “grew” …. and grew, and grew, and grew.