Gwangi is the titular character and main antagonist in the 1969 classic, The Valley of Gwangi. He is described as a male Allosaurus.
Gwangi was the apex predator, or top pretator in his area, similar to the tyranosaurs that lived in Hell Creek, Montana durring the Late Cretaceous. Gwangi defeated any dinosaur in his path, which means he wasn't too scared when he encountered humans. After captured, and set free, Gwangi continued his agressive behavior, and starts fights with the other circus animals (Elephant). Eventually Gwangi dies in a fire and faced a horrible death under the falling rubble of the church he was led into.
A creature of legend, Gwangi lived in the hidden valley in Mexico. When a group of cowboys got their hands on a miniature horse that hailed from the valley, the tiny creature was kidnapped and released in the valley. The original owners of the discovery had followed after it and entered the ancient valley. Once inside, they had to fend off and kill an attacking Pterosaur and save a young boy named Lope from being its next meal. After killing the flying attacker, they take chase of a smaller dinosaur they hoped to catch, but before they could, Gwangi appears around a corner and quickly seizes it in its maw. The gigantic dinosaur begins to feast on the dead Pterosaur before it discovers the lone Prof. Bromley. Before Gwangi could kill the human, a Styracosaurus confronts him. Realizing the easiest meal would be the freshly killed Pterosaur, the dinosaur turns around and gathers the flying creature in its maws and leaves to enjoy its meal.
The cowboys were forced to spend the night in one of the valley's many caves and to protect themselves, dug a large pit outside the cave. Unfortunately, the trap was fumbled that night when Prof. Bromley fell into it. The next morning, while Tuck was refilling his water cantina, Gwangi appeared. The cowboy ran back to the cave where the others tried to drive it off with spears. The attacks failed and Thuck ran off, making Gwangi follow him away from the others. While Tuck had Gwangi distracted, the others gathered their horses and ropes. The cowboys tried to lasso the dinosaur, but the creature proved too strong. In the midst of the battle, the Styracosaurus reappeared. Once the cowboys saw, they quickly dropped the ropes and fled back to the cave. The horned dinosaur charged the Allosaur and the battle began. Gwangi latched his jaws onto the saurian, but the horned creature managed to gore him over. One of the cowboys charged in, spearing the Styracosaurus. It didn't take long fir Gwangi to vanquish the creature and leave it for dead as he took off after the fleeing humans.
Gwangi managed to kill one of the cowboys but the creature couldn't fit through the valley's entrance. As the beast forced his way through, the opening collapsed, knocking the dinosaur out cold. They built a gigantic wooden wagon and carted the beast back to town where it'd be put on display for the world to see. As hundreds gathered to see the strange beast, one of the followers of Gwangi (people who viewed Gwangi as a God) snuck into the creature's pen and unlatched several parts of it. As the curtains lifted, the people saw the magnificent dinosaur holding the man in his maw. Before the curtain could be re - lowered, Gwangi began to knock the unlatched section of the pen down. The creature was released and quickly found a meal out of the elephant that served as a pre - show. The Elephant attempted to take down the dinosaur, but the creature's maw proved to much and eventually vanquished the mammal.
Gwangi emerged from the arena and began its hunt on the fleeing people. The masses fled into the large cathedral. The people tried to close the door, but Gwangi's bulk pressed against it and forced the large door open. While most of the people fled out the other side, T.J, Lope, and Tuck remained inside. The creature began its hunt for them until Tuck got its attention via chair throwing and yelling. As T.J. and Lope fled, Tuck tossed a flag pole strait into Gwangi's ear, allowing the duo an easy escape. As the three humans fled and the large dinosaur screamed in pain, Tuck tossed one of the torches at the creature, starting a large fire. As the flames raged, the creature was slowly burned to death. As the creature fell dead, the entire cathedral fell with it, ending the life of the beast.
- Harryhausen originally intended for Gwangi to be an Allosaurus, but based the design on a Tyrannosaurus.
- Gwangi's apparent color changes several times over the course of the movie because there was so much animation to do that Harryhausen did not have enough time to do proper color testing.
- Gwangi is a native American word that means lizard.