The Smiling Mailbox is a sentient robot built by Gyro Gearloose.
Description[]
This sentient red mailbox with a smiling face was created by Gyro Gearloose in the early 2000's to serve as his personal mailbox. Presumably, the point of the Mailbox was to act politely to the mailman, and also to report to Gyro about what important mail (if any) he had received.
Behind the scenes[]
This Mailbox was only ever seen in the 2003 story Donald Duck and the Alternate Lives.
Oddly, the Smiling Mailbox is redundant with a preexisting character, Posty — which may be why he was never used again.