Marbles.
Strip from October 8, 1982.
Marbles is a minor animal character in Charles M. Schulz's comic strip, Peanuts. He is one of Snoopy's brothers and is reportedly the smartest one in the family. Marbles' main feature is his floppy, spotted ears. In his first appearance in the strip, he is also depicted as wearing shoes.
History
Marbles' is first mentioned on September 23, 1982, when he sends Snoopy a postcard. Snoopy is so surprised to hear from Marbles that he falls off his doghouse, referring to Marbles as his "long-lost brother" whom he has not been in touch with in years. Marbles explains in the postcard he has lost his home and asks for Snoopy's help in finding a new one. He arrives in town on September 27, 1982, where he accidentally ends up at Peppermint Patty's house instead: he first appears on the following day, when Patty lets him in so he can wait for Snoopy inside. The two brothers reunite on September 30 and Marbles proceeds to stay with Snoopy for a few days. He explains he has lived with "four or five" different families, and went into research for a while, studying why some dogs walk at an angle. His conclusion is "...it's to keep their front feet from hitting their back feet."
In the strip from October 5, 1982, Marbles finds his brother pretending to be the World War I Flying Ace, preparing to do battle with the Red Baron. Marbles finds everything confusing when Snoopy allows him to join in with the game. Unlike Belle and Spike, who share imaginary World War I adventures with Snoopy in other strips, Marbles is unwilling to participate in the fantasy. He insists that what Snoopy describes as an ambulance is really a shopping cart and that Snoopy's Sopwith Camel plane is just a doghouse. Soon afterwards, a confused Marbles leaves the neighborhood.
Marbles appears with the rest of Snoopy's brothers and sisters, including two who had not appeared or been named in the strip, in the animated television special, Snoopy's Reunion, which originally aired on CBS on May 1, 1991. He plays the banjo in the special. He also appears in a flashback in I Want a Dog For Christmas, Charlie Brown. Marbles' appearance is different in the animated television specials, he is not depicted wearing shoes and does not have circles around the pupils of his eyes like in the comic strips.