One night, Littlefoot's grandfather tells the children a legend about "The Lone Dinosaur", a legendary Longneck who protected the Great Valley from the most ferocious Sharptooth to ever live. During the fight, the Sharptooth was killed and the Lone Dinosaur suffered a scar across his right eye. Soon after the battle, a huge monolith resembling a sauropod with life-sized Sharptooth teeth arranged around his neck came out of the ground during an earthquake. The dinosaurs called it "Saurus Rock". The legend also states that if anyone damages the monolith, bad luck would descend upon the Valley.