Tinkerbell the half Bulldog half Mastiff as a puppy at 7 weeks old weighing 13.2 pounds wearing a pink shirt. Her mom was the English Bulldog and her dad was the Mastiff.
The Masti-Bull is not a purebred dog. It is a cross between the Bulldog and the Mastiff. The best way to determine the temperament of a mixed breed is to look up all breeds in the cross and know you can get any combination of any of the characteristics found in either breed. Not all of these designer hybrid dogs being bred are 50% purebred to 50% purebred. It is very common for breeders to breed multi-generation crosses.