A woman was sexually assaulted after a night out in Bolton.
The attack happened on Corporation Street in Bolton town centre at about 3.30am on November 6.
Police have today released a CCTV still of the suspected offender and are appealing to anyone with information about his whereabouts, or the attack itself, to come forward.
The woman, 18, left Courtney's Bar and walked to the taxi rank on Bank Street. The offender followed her and threatened to punch her in the face her unless she gave him a kiss.
Frightened she would be attacked, she kissed the man and then hurriedly left the taxi rank.
However, he again followed her down Corporation Street and then sexually assaulted her.
The offender is described as being white, in his late teens, about 5ft 10in tall, of a slim build and was said to have very sharp teeth and ears sticking out. He had short dark hair and was wearing dark blue jeans, a grey adidas jacket with a black body warmer over the top.
Detective Constable Dave Fox said: "This young woman was subjected to a prolonged attack at the hands of the offender and understandably she is extremely upset.
"She had simply been enjoying a night out when she was confronted by this man, who used the threat of violence to intimidate and frighten her before sexually assaulting her.
"The young victim deserves justice and to see her attacker behind bars, so I would appeal to anyone who either witnessed the assault or who knows the identity of the offender to come forward.
"I understand people will be anxious. While we believe this was an isolated incident, we need to apprehend this man so I would stress that if anyone does have information that they come forward."
Anyone with information should call Bolton CID on 0161 856 5757 or the independent charity Crimestoppers, anonymously, on 0800 555 111.