A man was knocked unconscious as he walked home through Cleethorpes in the early hours of Sunday.
The 29-year-old was assaulted in Grant Street between 2.30am and 3am.
He was taken to Diana, Princess of Wales Hospital, Grimsby with serious injuries.
Humberside police have appealed for witnesses and are looking particularly for a man in his late 20s in a black trilby hat.
The victim was walking home alone after a night out in Cleethorpes. He approached a group of around 20 people. None of the group were known to the man.
As he made an attempt to walk past them, he was assaulted. He was knocked unconscious and sustained a number of injuries to his face and body. He was later treated in hospital.
Police hope to trace a man who left in a taxi shortly after the incident.
He is a white male, aged in his late 20s and around 5ft 7ins tall. he had facial hair, was of a medium build. He was wearing a black trilby style hat, a black three-quarter length coat, black trousers and he was carrying a bag, of a similar size to a laptop.
Anyone who may have information was asked to call Humberside Police on 101 quoting crime reference 2050677.
