A cyclist was "repeatedly punched" by a motorist at the entrance to a Northampton park, police said.
The man was pulled off his bicycle at Thornton Park between 07:50 and 08:05 BST on 15 June, and attacked by the driver of a silver SEAT Alhambra.
Northamptonshire Police said the assault followed an "incident" with the driver in nearby Mill Lane.
The victim suffered minor injuries to both his head and face. Detectives have appealed for witnesses.
The force said once the cyclist was on the ground, the driver got on top of him and repeatedly punched him. The bicycle was also damaged.
The attacker has been described as a white man in his late 30s to early 40s, 5ft 8in (1.7m) tall and of stocky build. He was wearing a white vest top and jogging bottoms.