Oscar was a student at East Texas Tech in the 1990s. He lived in a room in Hudson Hall with his roommate Darren.
One day, he answered the door when Sheldon Cooper complains about the music. He tells Sheldon it is the video game that Darren is playing on his console. He tells Darren that Sheldon had beat Adira, who invites him in. Later on, they want to get Chinese food. A few days later, he plays Dungeons and Dragons with Sheldon, Darren, and Abbey. He helps Sheldon get better after having too much candy and soda. (A Lot of Band-Aids and the Cooper Surrender)
One day, he was in his room, when Darren invited Sheldon and Paige Swanson over. He met Paige and talked to them. (A Solo Peanut, a Social Butterfly and the Truth)