Randy Marsh normally wears black pants and a blue button shirt when in public, but can be found at home in just his underwear. At one point of the game, he is seen in blue pajamas. After this, he's seen in his usual outfit for most of the game. During Beat Up Clyde, Randy wears his own larping outfit, but reverts to his regular outfit after the game is done.
Randy Marsh can be met before his role in the story begins if the New Kid enters Stan's house. Randy's role in the story begins when the New Kid is abducted by aliens and the New Kid manages to break free of the alien probe and Randy helps him find a way off the ship and is freed. He friends the New Kid on Facebook and then leaves the ship.
He's met the next day at the PTA meeting at the Community Center and tries to get the New Kid to explain what happened with the alien ship, but due to the New Kid's not talking, it doesn't happen. The New Kid tries to get a picture of himself with the "Fuck the Conformists" sign the Goth Kids insist he hold up at the PTA meeting but Randy stops him and gets him to help find out what's going on with the Taco Bell (Actually the Government) in exchange for the picture. Randy then proceeds to teach the New Kid the Sneaky Squeaker and sends him on his way.
After the New Kid returns with the audio recorder, Randy takes the picture for him and thanks him for his help. Randy reappears later in the story when the New Kid has snuck into the abortion clinic and is trying to find out why Taco Bell wants to know abortion information and the New Kid has to give him an abortion while dressed up as a doctor so they won't be shot by soldiers. Afterwards, Randy remains behind and isn't seen again in the story until the attack on Clyde's Fortress where he reveals that there's a Snuke up Mr. Slave's ass and the New Kid is required to go in and disarm it and Randy praises him. Randy isn't seen for what's left of the story outside of if the New Kid visits the Community Center.
- Despite earlier trailers showing him teaching the New Kid the Nagasaki fart, he only teaches him the Sneaky Squeaker in the actual game.
- Randy is one of the only adults in South Park that praises your farts and comments on it.
- Randy is the only parent listed with his first name on Facebook and the only adult whose profile picture does not feature his default attire from throughout the series.
- Unlike other parent characters, the subtitles show Randy and Sharon with their full names.
- Even before teaching the New Kid the Sneaky Squeaker, Randy will still say, "You've been practicing." when you fart on him before learning it. He can even say this during the first time you meet him in Stan's house.