Stanley (teddy bear)

Stanley (formerly Arty and briefly Chico  [named by Vicita]) is Arthur's teddy bear. His grandmother gave it to him on his third birthday (seen in a flashback.) Arthur once let D.W. borrow him when her Blankie was missing.

Desperately Seeking Stanley
Arthur finally gives him up in a garage sale to Vicita. She decides to name him Chico but later on she trades him for a sticker to the Tibbles. Arthur worries, thinking the Tibbles would destroy him. He discovers that the Tibbles gave it to their Grandmother, and she patched him up. Arthur tells her she can keep it, but then he runs and take it back saying "Actually, I think I'll keep him for this weekend."

Trivia
Although an episode revealed that Arthur gave Stanley to Mrs. Tibble, later episodes show Stanley in the background in Arthur's room.