Oscar George Bluth is the twin brother of George Sr. Oscar is notably different due to his large mane of hair he's been able to maintain thanks to his stress-free, stoner lifestyle unlike his brother. Oscar has been known to been having an affair with Lucille.
Lucille: I want you out of the house.
Oscar: Oh, I want you everywhere.
Oscar: Ok, but I never meant to break up your family. Your mom called me for a reason. I-I don't think she's happy.
Buster: No, she's happy. She's just mean all the time.