Ark's latest dinosaur, the Giganotosaurus Furiosa, is a bottomless well of rage that can eat its way through stone walls and unseat riders whenever it has a temper tantrum. It's slow, but with every hit its "rage reaction" makes its bite more powerful and it gains more stamina. The developers refer to it as a "captial beast of war"—the Super Star Destroyer of the dinosaur world, then.
The developers confirm that "fighting a Giganotosaurus directly is always a bad idea", and not only because of its tendency to bite harder when enraged. It can turn on fellow dinosaurs and hunters during tantrums, and has zero respect for buildings. It reminds me of the Horned Reaper from Dungeon Keeper. He can break out of most prisons you can ever build for him, so you're better off keeping him calm and happy. Or else.
Ark is being updated regularly at the moment. The dino babies and breeding updated arrived three weeks ago, and the world was invaded by mighty skelesaurs during Halloween.