Dweeb is one of the supporting protagonists in We're Back! A Dinosaur's Story. He is a hilarious green duckbilled Parasaurolophus and is voiced by Charles Fleischer.
Just like his fellow dinosaur friends, Dweeb was retrieved by Captain Neweyes and fed Brain Grain cereal, becoming intelligent and friendly in the process. He is first seen eating hot dogs with Woog the Triceratops and Elsa the Pterodactyl, when Rex the Tyrannosaurus Rex, another dinosaur fed Brain Grain, shows up and introduces himself. Dweeb tells Woog they've eaten 250 hot dogs before introducing himself to Rex and adding mustard on his hot dog. When the other dinosaurs express guilt over their past actions for when they were wild, Dweeb says that they've evolved as a result of their consumption of the Brain Grain.
After the hot dog lunch, the dinosaurs meet Captain Neweyes, who explains that he fed them Brain Grain so that he could grant childrens' wishes on seeing real dinosaurs. Amazed at seeing so many kids wish they could see a real dinosaur, Dweeb and the others agree to follow Neweyes' request
They travel to the middle future and are dropped off at the Hudson River after being told to find Dr. Bleeb and the Museum of Natural History of New York City. While admiring the beautiful city, they meet Louie, a boy who's running away to join a circus. They agree to accompany him as they go to the circus. When Rex falls into the river and nearly drowns, Louie uses a crane to help him back onto dry land. Dweeb and the other dinosaurs help by keeping the crane from being pulled into the water under Rex's heavy weight. Rex is rescued, to everyone's relief, and they start exploring the city.
While hiding in an alley to avoid being spotted, Louie takes flight on Elsa to find a way to get to Central Park. While waiting, Dweeb is forced to pull a hungry Woog back into the alley. He loses his grip and falls into the alley, crashing into some trash cans. He comes out (with a banana peel on his snout) upon seeing Louie and Elsa come back with a new friend, Cecilia Nuthatch. After introducing themselves, they all join the Macy's Thanksgiving Day Parade, acting like robots so they could reach Central Park with ease. However, during the parade, Rex starts singing "Roll Back the Rock to the Dawn of Time" after hearing numerous children wish to see a real dinosaur. The song catches the audience's attention and they dance with Rex. Dweeb and the other dinosaurs worry, but nothing seems to go wrong until the crowd eventually discovers that Rex, along with Woog, Elsa and Dweeb, are real dinosaurs. As the crowd flees, Louie and Cecilia are separated from the dinosaurs, but tell them to get to Central Park, where they'll meet up with them. Unfortunately, the dinosaurs learn that Professor Screweyes, Neweyes' evil brother whom they were told to avoid, is in Central Park running the circus. Before they could warn their friends, they are chased by the police around the city. Woog and Dweeb take a motorcycle, but get separated. Dweeb ends up driving down into a subway and riding through a moving train. He introduces himself to the passengers before getting out and driving down the track. Dweeb ends up above ground again, where he reunites with his fellow dinosaur friends and loses the cops.
After losing the cops, Dweeb and the other dinosaurs go to Screweyes' circus to save their friends, but are too late, for Louie and Cecilia have joined the circus after signing a contract in their own blood. However, Screweyes strikes a deal with the dinosaurs; if they take his Brain Drain pills and revert to their wild selves, he will let the kids go, otherwise, he will keep them for his show. Dweeb tearfully agrees, and the other dinosaurs also agree. As a result, Dweeb is reverted into his wild form once again.
At the night of the show, Dweeb and the other dinosaurs are chained and can only watch as Rex breaks loose of Screweyes' control and tries to kill him. However, Louie manages to convince Rex to put him down, and Rex returns to his friendly self again. After hugging Elsa and Woog, returning them to their friendly selves as well, Louie and Cecilia hug Dweeb who, after a funny transformation, becomes his friendly self again, and happy to see his friends again. Captain Neweyes later shows up to take the dinosaurs and kids home.
The following morning, at the Museum of Natural History, Dweeb is the third to introduce himself to the visiting kids. He and the other dinosaurs look upon the excited kids with happy faces as they talk and have fun with them.