Lisa's unknown relative

Lisa's unknown relative is the unknown relative of Lisa and John. He cannot be the father of them because Unknown Male Adult Rabbit (Number 2) is, however he may be the old design but it is unlikely to be true. He may be an uncle or a cousin to them.

Muffy's New Best Friend
He was seen with Lisa at the cinema box office in Muffy's New Best Friend.

Arthur Loses His Marbles
He was seen playing Bingo in the introduction and turned around to stare at Thora Read when she was being loud about her victory.