A man was punched repeatedly to the head and face by an unknown attacker outside a Kettering bar.
Officers are appealing for witnesses following the attack outside Brooklyn Bar in Ebenezer Place at about 4am on Saturday, March 23.
A Northamptonshire Police spokeswoman said: "He was described as white, 5ft 10in and aged about 30.
"He had reddish hair and beard and piercings down the back of one ear.
"He was wearing a red long-sleeved knitted jumper."
Anyone with information should contact Northamptonshire Police on 101. Alternatively, they can call Crimestoppers anonymously on 0800 555111.