He has two sisters, named 3 and 4.
Misery, My Sweet Babboo Edit
In this skit, 555 is one of the kids who skates on the ice, together with Lucy, Pigpen, Frieda, Snoopy and Linus, until Franklin points out that they're late for the christmas rehearsal. Frieda, however, tells him that they just can ignore the one in charge (which is Charlie Brown) and dance repetitively, to which 555 replies that he loves to dance repetitively, and they all leave, ignoring Linus who got tossed into a tree by Snoopy, leaving him for dead.
Ren McCormack Edit
In this segment, 555 95472 is seen dancing with the other Peanuts characters. He had no lines in this segment.