Police arrived to find him running through a nearby paddock.
When he was apprehended, McArley produced a large plastic container from his pants which contained 12.5g of cannabis and 12.2g of crystalline rocks.
Scientific analysis of the substance found some was a cutting agent often used to increase the weight of illegal drugs and the rest was "MDPBP hydrochloride" - the primary ingredient in bath salts, producing a similar effect to methamphetamine.
McArley admitted to police he had "a very bad drug habit".
He appeared in the Dunedin District Court this week having admitted possessing cannabis, threatening to kill, assault and one of careless driving causing injury.
The defendant first came before the court after crashing into the rear of another car on April 28 last year.
The victim was waiting at an intersection in Green Island when McArley slammed his BMW into him.
Police on the scene noted his slurred speech and bloodshot eyes and a sample of the defendant's blood showed traces of THC (the active ingredient in cannabis) and the class-C drug phentermine.
He later admitted he was "off his face" at the time.
Despite the drugs problems that gave rise to the two offences within weeks of each other, McArley was granted bail.
He kept his nose clean until February when another strange incident unfolded.
High on MDMA, McArley visited the home of his mother's neighbour.
When the man at the home tried to calm him down, the defendant wrapped both arms around him tightly and shuffled around the property while holding him.
McArley's mother arrived home which prompted him to yell "I'll f . . . kill you" at her.
Still with the male victim clamped between his arms, he tottered across the road towards his mother where he repeated the threat several times.
McArley released the neighbour and was finally restrained until police arrived.
Counsel Alex Bligh said her client was in the grip of a serious drug addiction at the time and took full responsibility for his actions.
He wanted to undertake residential rehabilitation, she said.
Judge Kevin Phillips said McArley had accumulated a range of convictions since 2000 including drug and driving offences.
He said the defendant talked about rehabilitation when it suited him but when the pressure was off was unmotivated to address his illicit habit.
McArley was sentenced to four months' home detention and 240 hours' community work.
He was ordered to pay more than $4000 in reparation and banned from driving for a year.
