Gigantoraptor is an incredibly tall dinosaur in Carnivores: Dinosaur Hunter. It is the largest member in Oviraptorosauria, a group of omnivorous to herbivorous theropod dinosaurs. It was added along with Carnotaurus to the March 8, 2013 Android update. The update for iOS featuring the creature was released on April 4, 2013. 
Carnivores: Dinosaur Hunter
Gigantoraptor is a very large pointable animal introduced in the March 8, 2013 Android update of Carnivores: Dinosaur Hunter. As its name suggests, Gigantoraptor is a gigantic, dangerous dinosaur. It is (visually) as tall or even taller than the Tyrannosaurus Rex, and is just as aggressive. Despite its massive size, Gigantoraptor is a very lightweight dinosaur, barely exceeding one tonne. Despite their size and lightweight bodies, they have incredible speed and can cover good distance in stride, making escape very difficult once the hunter has been compromised. Like the Tyrannosaurus, Gigantoraptor does not flee when it hears gunshots, but instead charges the hunter, giving the hunter very limited time to bring it down. Also like Tyrannosaurus, Gigantoraptor is relentless in attack, never losing sight of the hunter and will continue to chase him across the island, even if he uses "relocate" to get away from one. Because of their acute senses, spawning in an area with a Gigantoraptor close by is often fatal. Like the smaller predators of FMM UV-32, Gigantoraptor actually leaps onto its target when attacking. These traits make Gigantoraptor an incredibly fearsome dinosaur to hunt.
Gigantoraptor is primarily green, but it features a blue stripe along its neck and back which allows it to blend in with most landscape backgrounds. It has a large black beak, most likely used for crushing its food, and large eyes. Gigantoraptor also sports red feathers on its arms and tail, and a red feathery crest on the back of its head. It is a very large dinosaur, with a skull up to a meter long. The Dinopedia suggests hunting young Gigantoraptor, as the dinosaur adds 140 kg to its weight every year. Gigantoraptor emits a loud, bird-like call, similar to that of the Oviraptor. It is presumably an omnivore, using its large beak to crush nuts and eggs as well as the bones of other animals. Like Oviraptor, Gigantoraptor is likely an attentive parent, and may use its long red arm feathers to shield its eggs from the elements during the many months of incubation. Gigantoraptor may be the tallest known theropod on FMM UV-32, though Tyrannosaurus and Giganotosaurus are longer and heavier.
Instead of being listed as "Very Dangerous" or "Extremely Dangerous" on the menu (as most theropod dinosaurs are), Gigantoraptor has this brief description: Enormous chicken that likes meat.
This was changed in a later update to "Extremely Dangerous".