A 14-year-old girl was filmed on a mobile phone as she was forced to strip naked before being beaten with stiletto heels in a 45-minute torture ordeal.
A court was told the attack was carried out by two other girls as a teenage boy egged them on.
The boy kept his phone running throughout the incident, which left the victim caked in blood.
The three attackers admitted assaulting the girl to the danger of her life. Sentence was deferred.
The High Court in Edinburgh was told the victim spent six days in hospital after staff at the Omni Centre in Greenside Place, Edinburgh, came to her aid following the attack in the centre’s underground car park on 23 January.
Advocate depute Alex Prentice QC, prosecuting, said the assault happened after the youngsters, who had been drinking cider, were thrown out of a cinema at the leisure centre.
As the two 14-year-old female attackers kicked and punched their victim, a 13-year-old boy kept up a running commentary as he filmed the incident.
He said at one point: “It’s only been five minutes of torture,” before telling the attackers to “pass the ball” as the two girls began kicking their victim’s head.
The boy also instructed: “Get the heels out” before both girls struck the victim with their high-heeled shoes, ignoring her screams and pleas.
He further egged them on: “Break her jaw, smack her head off the wall.”
The boy then said: “It’s like Resident Evil”, in a reference to the horror film and video game series.
The terrified girl was again kicked as the boy urged: “Put her to sleep” and told her: “You’re going six feet under.”
She was made to lick blood off the attackers’ shoes because the boy stated his mum would “go daft” if she saw it.
The girl was also struck with metal signs torn from the car park wall before a noise disturbed the attackers and they ran away.
Dried blood
Police were later called to a disturbance at a young person’s unit on the other side of Edinburgh and found the one of the attackers without her shoes and covered in dried blood.
Her female accomplice was found by officers the following day after being reported as a missing person.
When they later questioned the boy, he asked them to look at the video on his mobile phone so they could see he had not taken part in the actual assault.
“These officers then viewed some of the footage and were horrified by its content,” said Mr Prentice.
The victim was taken to Edinburgh Royal Infirmary, covered from head to toe in dried blood.
She had six head wounds “consistent with blunt trauma and having been caused by the tip of a stiletto heel.”
Lord Malcolm called for background reports and ordered the attackers to be locked up pending sentence next month.
“I do not intend to have the film played in court. I shall reflect on whether I will view it privately”, he added.
None of the attackers or their victim can be identified for legal reasons.