A 23-year-old woman was hit over the head with a bottle on a busy Brighton street.
And the attacker dragged the victim along the street by her hair.
Sussex Police urged anyone who saw the assault in Lewes Road to get in touch.
It happened near the Forfars Bakery at about 12.30am yesterday (Thursday 30 May).
The victim was badly shaken but did not require hospital treatment.
The suspect was described as black, about 37 years old, 5ft 3in tall, of medium build and with very short black hair. He was wearing a grey tracksuit, black trainers and a baseball cap.
Detective Constable Liz Hough urged anyone who saw the incident to call Sussex Police on 101 or the independent charity Crimestoppers anonymously on 0800 555111.
Sussex Police said that the victim and assailant were known to each other. Police inquiries are continuing to trace the man.