A baby is in hospital with a serious injury after being struck in the eye with a golf ball.
The three-month-old boy was hit at a playground in Sheldon, Birmingham at 20:40 BST on Friday.
A 36-year-old man was arrested on suspicion of assault and is also in hospital, West Midlands Police said.
The force said the man and the baby were not believed to be related and urged anyone with information to contact them.
Officers were called to the scene, in a park outside Radley Court on Sheldon Heath Road, by ambulance crews.