Romper Stomper was Eric Cartman's cellmate at the Alamosa Maximum Security Juvenile Hall, so named for the Hasbro toy Romper Stompers he always used. He wants cigarettes and requests Cartman to retrieve them when Stan Marsh and Kyle Broflovski visit in return for helping him break out of prison. Even more desperate is his desire to see Disneyland. He seems to have a love for movies, seen when Cartman and Romper Stomper attempt to escape. During the escape, Romper Stomper trips and falls and tells Cartman to carry on without him.
Cartman obliges and continues to leave until the security guards catch up to the two. The guards let Cartman go free, due to him being pardoned, however, Romper Stomper is to return to the facility. Cartman later visits Romper Stomper, with the whole of Disneyland hidden in his rectum, allowing Romper to finally see it.
On the surface, Romper Stomper appears to be a tough, menacing bully. The other prisoners are afraid of him and he also leads the boys in initiating Cartman, asking him for a good reason why they shouldn't break his arms. He is shown to be manipulative. He promises Cartman to help him break out of prison if he smuggles cigarettes for him, but later he reveals that he was just making use of Cartman to get what he wants.
However, beneath his tough exterior, he is shown to be kind and thoughtful. He feels sympathy when Cartman cries upon learning that he lied about helping him escape. When he trips and falls during their escape, he tells Cartman to go on without him and even gives him his Romper Stompers. Romper Stomper says he does not believe in friendship but appreciates it deep down. When Cartman says he considers him as a friend just before he escapes, he smiles. At the end of the episode, he is very excited when Cartman comes to visit him, as he has never had a visitor before.
Romper Stomper has messy black hair, a teardrop tattoo, and with two other tattoos on his arms. He wears an orange prison suit, black shoes and is taller than a 4th grader, he looks the same size as Shelly Marsh.
Romper Stomper's appearance has changed a bit in South Park: The Stick of Truth, he's designed more like a 4th grader, but still the same size, he no longer uses his yellow cups and his tattoo is different too.
- Romper Stomper can be seen using Romper Stompers, the two yellow cups strapped to the bottom of his shoes, a toy made popular in the 1970s. 
- Romper Stomper's character is likely based on Hondo's character in the film, Romper Stomper, a film about hate crimes.
- Romper Stomper appears in South Park: The Stick of Truth in the South Park Police Department jail cell. He gives the player a quest to get the key to break him out. His voice sounds higher than on the show.