Charlie (Oh Brother, Where Bart Thou?)

Charlie is a boy who was briefly "adopted" by Bart Simpson.

History
Bart decides he wants a brother after seeing the bond between Lisa and Maggie. After failing to get Marge pregnant, and then discovering that if Marge was pregnant, he might get a third sister, he decides to try and adopt a kid from the orphanage. His request was turned down because he wasn't old enough. When Bart is leaving the orphanage Charlie sees how badly Bart wants a brother and sneaks out. The next day when Bart wakes up, he sees Charlie in his room. They were having fun until Bart took him to a scary film, and found out how hard having a little brother is.

Bart then returns Charlie to the orphanage (after being convinced by Lisa to), the next day when Bart goes to visit him he finds that he has been adopted by a family with 6 girls.