It is a scenario which has become all too familiar for Hawke's Bay police officers since K2 and its allied synthetic cannabinoid products came on to the scene.
A call comes in late at night from a distressed parent.
Their son is home - but he's not the same son who ventured out of the house a few hours earlier.
They recognise his face but do not recognise his behaviour.
It is aggressive and unpredictable.
Their boy is out of control and they need help with him.
And as has happened on too many occasions, the young man lashes out at the wrong person at the wrong time and he is restrained and bundled away into the police car.
Up until that night he had never come to the attention of police and was just another family kid.
"We see it a lot - too often," Hawke's Bay Police Inspector Andy Sloan said.
"We've seen the major impact K2 has had on young people. Their normal behaviour becomes erratic and unpredictable ... we have seen an increase in violence and that is down to K2."
Mr Sloan said as well as create often dangerous situations for officers and health and social agencies to deal with, K2 had become a recognised driver of crime.
It had become like any drug - a desirable commodity which cost money (about $20 a packet) and that meant those who used it regularly had to find the cash to keep the habit going.
"So they steal," he said, adding that several offenders had confessed that K2 had been behind their activities.
Confessing to K2 use was not uncommon, Mr Sloan said.
"Because they know it's not illegal to have ... well not until May 9."
On that day it becomes a banned substance.
For police the workload in having to cope with the effects of K2 has spiralled upwards.
As well as deal with out-of-control users in their homes or on the streets, officers then had to "manage" them.
"They are in our care and we go through a range of steps while they are in custody," Mr Sloan said.
Medical crews were sometimes called in if the effects had clearly became serious.
"These usually normal people completely change."
There had been cases locally where mental health agencies had become involved with young people whose temperament and behaviour had radically altered - to the concern of friends and families who had seen the changes emerge.
Officers have been attacked and assaulted, and while Mr Sloan did not have immediate access to the number of K2-sparked incidents attended every week he said it "keeps us pretty busy".
"It takes up a lot of our time and it's something we could very much do without."
Frontline staff are trained within a "tactical options framework" and quickly access the situations they walk into. There was no specific guideline for approaching someone affected by K2.
"It is about managing a situation - managing people."
In terms of unpredictability it had become more severe in many cases than the effects of alcohol.
Mr Sloan said apart from the violent and criminal side effects of K2, the damage to health was another major factor in police wanting it off the streets.
"We don't know what the long-term effects of these synthetic cannabinoids could be. But we do know about the short-term effects we've seen it have on relationships and families."
Although legal to sell, Hawke's Bay Police have collected a list of sale points and it numbers about 40 across the region.
Forty too many for their liking.
"We have strongly urged people not to sell it because we see what it does and we do not want it in our communities."
Nor in schools, Mr Sloan added.
"We have had incidents here where there have been reports of kids smoking it."
Youth Education officers had worked with staff in some cases while some schools were understood to have taken their own action.
To the community groups and individuals who lobbied and appealed for shops to take it off the shelves he simply said "good on them".
"We support that stance."
And his over-riding summation was a simple one.
"We don't want to see this out there. We have to deal with the fallout and it uses up a lot of our time. We see what it does to people and at times it is frightening."