Oh Brother is the 12a episode of the first season of The Marvelous Misadventures of Flapjack.
Flapjack is criticized because of his baby-like behavior. K'nuckles tells Flapjack too grow up resulting in Flapjack being turned away until he is accepted by K'nuckles. Later Flapjack asks Bubbie where babies come from. She at first attempts too change the subject probably because of the mature nature of reproduction. Immediately after, Flapjack asks Bubbie where little Brothers come from. Bubbie then tells Flapjack about the history of how she found him drifting upon the sea. Flapjack then sets out on a quest too find a little brother in a similar manner as Bubbie did.
Flapjack notices a group of ducks floating on top of a drifting plank. Flapjack picks up and takes a duck believing it to be a baby with missing body parts. Later Flapjack returns too K'nuckles finding him asleep. Flapjack takes body parts from K'nuckles to give too his new seagull "Baby brother" such as his lips, earwax, a toenail, etc. Flapjack spends the day reminiscing with his new so called "Baby Brother". Eventually the duck flies away and Flapjack stumbles upon a small boy. The boy is quite annoying, so Flapjack tells him too grow up, following to the boy stating he is actually 38 years old despite his adolescent appearance. (His voice changing from adolescent to mature) The camera is then zoomed too the boys face showing him looking quite old and UGLY! Flapjack returns to Bubbie's mouth where K'nuckles then wakes up. Surprised, K'nuckles panics because of his missing body parts. Ironically he begs Flapjack to help him in a childish manner and Flapjack dismisses him as K'nuckles did to him earlier in the episode. We then see the disturbing 38 year-old boy/man again doing a creepy face.
This is the first episode not to show a "THE END" card.
We learn that years ago, Bubbie found Flapjack in seaweed when he was younger.
Hawaiian Train is played in the background when Flapjack takes off K'nuckles' body parts. This can be heard in most Spongebob Squarepants episodes.
The "Do You See" line from this episode was later heard in Come Home Cap'n as part of K'nuckles' song. But looked different than the orgininal.