Pigpen has affixed to him the dirt and dust of past civilizations.
Pigpen

First Appearance:
July 13, 1954
He may travel in his own personal dust cloud, but Pigpen’s mind and conscience are clear. He’s confident in who he is and carries himself with dignity and respect. He treats others well and hopes they will do the same for him (they often do not, but he perseveres). Pigpen considers it a point of pride that he is cloaked in the ‘dust of countless ages.’
Did You Know:
Charlie Brown is the one kid that unconditionally accepts Pigpen for who he is, even defending his uncleanliness in one strip.
"Pigpen is a human soil bank who raises a cloud of dust on a perfectly clean street and passes out gum drops that are invariably black." —Charles M. Schulz
Interests:

Archaeology

Mud Pies
When Violet makes mud pies, Pigpen is her best customer!

Politics
Pigpen aspires to be class president one day.