#AmericanBully #AmBully #American #Bully #Dog #Pets #Pitbull The American Bully was developed from the American Pit Bull Terrier, with outcrosses from assorted bulldog and mastiff breeds, in order to create a dog for the pet trade rather than the dog pit. The American Bully lacks the extreme dog aggression of the APBT, but often inheret the heightened protection instinct of the mastiff.