Size and Weight:
About Majungatholus (Majungasaurus):
Although it almost certainly wasn't the habitual cannibal portrayed on TV, there’s good evidence that at least some Majungatholus adults preyed on their own kind: paleontologists have discovered Majungatholus bones bearing Majungatholus tooth marks. What's unknown is whether the adults of this genus actively hunted down their living relatives, or simply feasted on the carcasses of already-dead family members (and if the latter is the case, this behavior wouldn't have been unique to Majungatholus, dinosaur-wise).
Like many other large theropods, Majungatholus has proven difficult to classify. When it was first discovered, researchers mistook it for a pachycephalosaur, or bone-headed dinosaur, based on the protrusions on its skull ("tholus," meaning "dome," is a root usually found in pachycephalosaur names). For this reason, some paleontologists have taken to calling this predator "Majungasaurus" instead.