Cranston made enormous contributions in developing his own character. Gilligan left a substantial amount of Walter's past unexplained so Cranston came up with his own backstory for the character. He even collaborated with costume designer Kathleen Detoro on a wardrobe of mostly neutral green and brown colors to make the character bland and unremarkable, and he worked with makeup artist Frieda Valenzuela to create a mustache he described as "impotent" and like a "dead caterpillar.” Cranston has said he was inspired partially by his elderly father for how Walter carries himself physically, which he described as "a little hunched over, never erect, [as if] the weight of the world is on this man's shoulders.”