Allosaurus is the main antagonist in The Land Before Time VI: The Secret of Saurus Rock.
The gang hid in a rotting log, which the Allosaurus grabbed in her jaws and threw it towards a ravine were it became lodged between each other like a bridge, the children then used the log like bridge to cross the huge ravine. The Allosaurus then tries to cross the unstable log after them, the sharptooth bites into log causing it to break sending her falling into the ravine five hundred feet below.
Later, when Littlefoot tries to retrieve a tooth from the supposed dead Allosaurus (so as to repair the damage to Saurus Rock), she was shown to have survived and chased after the young longneck. Littlefoot managed to escape the Allosaurus by getting though a hole in a rock wall while the sharptooth tried to break though the wall,but Littlefoot ran into a Tyrannosaurus then Doc and Grandpa long showed up and the two sharpteeth were beaten when,the two longnecks pulled a large spire of rock down on them presumably crushing both carnivores to death.