The Prophet (pbuh) used to joke with the small child of one of the Sahaba, a boy called Abu 'Umayr, who had a small bird he used to play with. One day he saw the child looking sad, so he said, "Why do I see Abu 'Umayr looking sad?" The Sahaba told him, "The nughar [a small bird, like a sparrow] which he used to play with has died, O Messenger of Allah"..
The Prophet (pbuh) began to gently joke with the child, saying, "O Abu Umayr, what happened to the nughayr?" [Nughayr: diminutive of nughar. In Arabic, this is a play on words, because of the rhyme between the boy's name and that of the bird]. Source: This story was reported in Hayat al-Sahabah, 3/149.
