Mailbox is a cheerful purple mailbox who lives at the foot of the pathway in front of the Blue's Clues house. In each episode, Mailbox delivers a letter after the host sings a special song called "Mailtime" and sits on the Thinking Chair. His letters contain video messages from children around the world that relate to the episode's topic.
Mailbox has a thick Brooklyn accent and likes to crack jokes. He wants to be a comedian when he grows up and has a collection of postage stamps. Although he is normally stationed on a stake in the ground, he can use an "extendo" arm to move anywhere around the house or the backyard.
He is voiced by Michael Rubin, one of the show's main music composers. Throughout the original series, Rubin was always credited under the stage name "Seth O'Hickory."