A man has been left seriously injured after he was assaulted by a man dressed as the Joker in a "brutal, unprovoked attack".

The 20-year-old suffered serious facial injuries and had to be treated at Aberdeen Royal Infirmary after the attack at Langstane Place in the city at about 11.30pm on Saturday.

The suspect was dressed as the Joker from Batman and was wearing white face paint with a lipstick smile along his cheeks, a purple suit jacket and trousers, white shirt and black shoes.

He was in his twenties, about 5ft 10ins and stocky. He had dyed green curly hair which he sometimes covered with a long black curly wig.

Before the attack, he was seen socialising with a man dressed in a black cape and another man in a grey boiler-suit with a mask and a wig at a bar on Belmont Street.

He tried to fight with people in Langstane Place and across from St Nicholas Cemetery before attacking the 20-year-old man near Bon Accord Street.

Pc Eamonn Ryan, of the divisional alcohol violence reduction unit (DAVRU) - which is leading the investigation - said: "I appreciate the bizarre circumstances surrounding this incident, however the reality is this person carried out a brutal, unprovoked attack on a member of the public and they need to be held accountable for their actions.

"Do you know anyone who went out for Halloween weekend dressed as the Joker? Did you see this person on Saturday night and have information which could assist in tracing him?

"We believe he entered the city centre from the Rosemount direction at around 8pm before heading to a bar on Belmont Street where he socialised with two other men - one dressed in a black cape and the other a grey boiler-suit with a mask and a wig.

"Just one punch can have fatal consequences and I don't think I need to stress that violent behaviour of any kind will not be tolerated.

"It is extremely disappointing that what was meant to be a night of fun has resulted in a person being seriously injured and we need the public's help to trace this person."

Anyone with information is asked to contact police on 101 quoting reference number 1242 of October 29, or Crimestoppers on 0800 555111 where callers can remain anonymous.