|“||I don't wanna be a lone dinosaur anymore!||”|
— Littlefoot when he runs into the Tyrannosaurus
In The Land Before Time VI: The Secret of Saurus Rock, a pair of Sharpteeth appear as the antagonistic forces of the film. They are a Tyrannosaurus and an Allosaurus respectively. The Allosaurus appears multiple times, including the climax, and the Tyrannosaurus only appears during the climax.
When Threehorn twins - Dinah and Dana - are playing on their way to Saurus Rock, they do not know they are being followed by the an Allosaurus. Before it can catch them it accidentally gets its head stuck in a redwood tree.
Later, it is encountered by Littlefoot, Ducky, Petrie, Cera, and Spike while they are traveling to get the twins back from the monolith. They mistake it for a tree trunk at first, but soon realize that it is the Sharptooth's foot, and run away as it escapes from the tree. It yet again fails when it gets its head stuck between two more trees.
After retrieving Dinah and Dana, during their journey back home the Allosaurus is encountered once again. The Allosaurus quietly sneaks behind Cera, and though her friends try to warn her, she believes they are playing a joke on her. Once the Sharptooth drools on her head, Cera realizes that it's really there, and she and her friends run for safety. The children hide in a rotting log, which the Allosaurus grabs in its jaws and throws it towards a ravine that they had crossed earlier, where it becomes lodged between each side like a bridge.
Although Cera briefly gets stuck trying to get out of a hole on the log, the children, save for Spike, manage to get to the other side, while their pursuer attempts to cross the unstable log after them. Spike remains stuck in the log, but while the Sharptooth tries to devour Spike, Littlefoot and Petrie free him. As Spike pops out, the Sharptooth misses Spike. It jumps at them and bites into the log causing it to break, sending the predator falling into the canyon below.
Later, during the climax, when Littlefoot attempts to retrieve a tooth from the apparently dead Allosaurus (so as to repair the damage done to Saurus Rock), it is shown to have survived, and chases after the young Longneck.
Littlefoot manages to escape the Sharptooth by getting though a hole in a rock wall. While the Sharptooth tries to break though the wall, Littlefoot runs into another Sharptooth, which is a Tyrannosaurus. Upon seeing the predator approaching him, Littlefoot shouts for help. Running under his legs, Littlefoot admits that he is in way over his head and that he doesn't want to be a Lone Dinosaur anymore. The Sharptooth turns and immediately goes after the young Longneck, who soon trips over a small rock and falls. Just then, a shadow appears over him. At first thinking it to be Doc, he is soon proven wrong when it turns out to be his Grandfather. Grandpa tells Littlefoot to run while he and the Tyrannosaurus fight.
Soon Littlefoot's friends arrive and watch with him as Grandpa effortlessly uses his tail to knock down the T. rex, tail-whipping the predator into a large rock and wrapping his tail around the sharptooth and headbutting it. As they cheer him on, Ducky soon points out that it's not over yet. The Allosaurus soon arrives and roars in anger (presumably for having to waste so much of it's time and energy, as Littlefoot was able to escape by moving past a large boulder that the predator had to destroy before getting through).
With Grandpa distracted, the Tyrannosaurus gets back up and knocks the elder away with his foot. Doc appears and pulls the Allosaurus to the ground with his tail. The Tyrannosaurus faces Doc, but Grandpa recovers and knocks the sharptooth away with his neck. When both Sharpteeth recover and charge at the two Longnecks, they easily move out of the way causing the Sharpteeth to crash into a rock spire. As the carnivores are down, the Longnecks pull both sides of the spire with their tails, causing it to break and crumble down, crushing the two carnivores to death.
Many fans were pleased to see the introduction of an Allosaurus to the franchise, but disliked that the sharptooth did not have the three-fingered hands like the real dinosaur had. Fans did not care much for the Tyrannosaurus, and thought of it as just another incompetent sharptooth.
- Some fans of the franchise believe that the Canyon Sharptooth is the ghost of the Meanest Sharptooth; bedevilling any dinosaur unfortunate enough to enter the canyon. This is thought because of their similar appearance and how the Allosaurus, fighting alongside it, did not seem to notice its counterpart in its territory. However, this could also simply be a coincidence; the first film's Sharptooth and Chomper's Father look nearly identical to both of the two Tyrannosaurus depicted in the film.
- Others believe that the Tyrannosaurus is the Meanest Sharptooth, still alive, living in the canyon. This is unlikely though, as the Meanest Sharptooth was defeated a long time ago, possibly a century. It would be unlikely that the theropod was still alive.
- Despite being an Allosaurus, the brown Sharptooth is only depicted with two fingers while the actual dinosaur had three. Despite this, she was shown with the accurate amount of fingers just as he is approaching the log that the gang is hiding in (just before he looks into the limb and sees Ducky poke out of it).
- Curiously, no one in the film questions why the two Sharpteeth are present in the Great Valley, a location which is supposed to be free of predators.
- However, as confirmed in the movie at one point, Saurus Rock is located in the outskirts of what use to be a part of the Great Valley.
- For some reason, the Allosaurus was credited in the credits for the movie, voiced by Danny Mann, but the Meanest Sharptooth and the Tyrannosaurus from the climax are uncredited.
- The Canyon Sharptooth is the last large Sharptooth in the franchise to have two red eyes, a trait common in early sequel sharpteeth that made them look more menacing and dangerous. Later sequels do not give large Sharpteeth red eyes, and instead give them human eye colors such as green and yellow which look less intimidating.
- The only exception is Red Claw, who has one red eye.