Gardai have expressed horror after a young thug filmed the brutal beating and stabbing of a 17-year-old boy with a broken bottle in a row over a phone.
The attack happened in the Waterpark area of Carrigaline, Co Cork, at around 10.20pm on Saturday.
Local people said a large group of teenagers were "rampaging out of control" when the attack happened.
Gardai are investigating both the savagery and the recording of it as a large group of teenagers watched but refused to go to the aid of the victim.
Despite the injured teen lying on the ground covered in blood, one teenager repeatedly tried to use his phone for a close-up recording of the victim's face.
When he was chastised by a girl and urged to leave the injured teen alone, he loudly challenged her and demanded that another person move so he could continue recording.
Footage also shows repeated attempts to stab and kick the victim, despite him lying defenceless.
One clip shows the victim's clothing being pulled up in an attempt to expose his back for further stabs.
"It is one of the most shocking things I have ever witnessed," a long-serving garda said.
"The behaviour of some of those present can only be described as disgusting."
Sinn Fein TD Donnchadh O Laoghaire said the incident was "truly shocking".
"It is deeply upsetting news coming from Carrigaline," he said.
"I am aware of videos of the incident circulating. Out of respect to the victim, please do not share.
"Please also be aware that sharing the names of people involved in the incident could undermine chances of convictions.
"If you have information, please go to the gardai. I wish the victim a full recovery and I hope justice will be done."
The helpless teenager was beaten and stabbed multiple times in the back and sides.
It is understood the attack was sparked by a row over a mobile phone.
The victim was rushed to Cork University Hospital, where he was in a stable condition last night.
His injuries are not understood to be life-threatening.
A second teenager was later arrested.