J.R.R. Tolkien’s posthumously published story about a toy dog is Roverandom.
Tolkien wrote Roverandom in 1925 after his son Michael lost a favorite toy dog while on holiday at the Yorkshire seaside resort of Filey. The story follows Rover, a real dog transformed into a toy, through adventures involving wizards, the Moon, and the sea.
The tale remained unpublished during Tolkien’s lifetime. It was edited by Christina Scull and Wayne G. Hammond and published in 1998, decades after Tolkien’s death. Its origins show how family incidents often prompted Tolkien to invent stories for his children.
Roverandom is separate from Middle-earth and should not be confused with Tolkien’s later short fiction such as Leaf by Niggle or Smith of Wootton Major. It is also distinct from the character Rover in other Tolkien notes and drafts, despite the recurring use of names connected with roaming or travel.