William likes toys.
Pretty sure that since his first birthday, William believes all toys belong to him.
The dog has a whole collection of only two, yes two, toys/chew things.
William naturally gravitates to exactly those two toys. Not the Elmo guitar. Not the magical singing train. Not the large number of Caterpillar trucks. Exactly the two disgusting, dog chewed, slobber-covered toys.
The dog doesn't mess with William's toys. He just asks that he gets to chew in peace.
William learned an important lesson in sharing when the dog (rightfully) took his toy back.