At first, Rhett boasts about himself and tells Ali truthless stories about him protecting his herd from Sharpteeth and convincing her that they were real, saying he did things such as build a mountain of rocks with his tail, and knock down trees so that Sharpteeth couldn't get by. Littlefoot, Cera, Ducky, Spike, Petrie, Chomper and Ruby decided to plan a scheme to convince Ali that Rhett had been making up all of his stories. There plan was to have Chomper act as a mean Sharptooth, pretend to be his prey, and ask Rhett to save them. The plan worked and Rhett ran away to his herd, showing Ali that he wasn't as brave as she thought. After he told the adults in the herd, they became convinced that Chomper was vicious and gave him chase. The Longnecks cornered Chomper, but the gang soon came to his rescue. When the Old One heard from the children that Rhett had been making up stories about Sharpteeth fearing him, and fooling Ali into believing him, she sternly told him that it wasn't good to tell lies, but also warned the other children that a Sharptooth attack was no laughing matter. After that, he apologized, and befriended the gang.
In the LBT-Humanization Series, Rhett has been known in the great valley as the dinosaur version of Johnny Bravo.