The drunk 26-year-old got into a car with his friend and accelerated hard through a red light in Caversham.
He crossed all four lanes of a nearby road while travelling at least 100kmh.
"The passenger was hanging on, frozen with fear," Judge Kevin Phillips said.
But the wild driving only served to stir Blunsdon further.
"I’m going to do some ****," the defendant said.
And he did.
Blunsdon saw a pedestrian walking along the footpath and pulled over to confront him.
"Without warning or saying anything, the defendant punched the victim to the face with such force he fell to the ground," a police summary said.
As the man lay defenceless on the ground, Blunsdon stomped on his head three or four times "in a full-force, downward motion".
The victim pleaded with him to stop but it was not enough.Blunsdon, circling the man, kicked him at least three more times in the back and the side of the head.
The victim tried to protect himself by curling into the foetal position, the court heard.
Despite the two having never met, Blunsdon told him: "you know my name, the next time you see me, this’ll happen again".
The victim suffered bruising, concussion and pain to several areas, which resulted in him making three visits to hospital over the days following the December 26 attack.He said he now worried who was behind him all the time.
"I don’t know why I was attacked," he said in his statement to the court.
"That’s outrageous behaviour of a highly criminal kind," Judge Phillips said.
Blunsdon initially pleaded not guilty to the allegations against him but before he was sentenced at the Dunedin District Court yesterday he admitted counts of dangerous driving, injuring with intent to injure, intimidation and unlawfully being in a building.
The last two charges related to his bursting into his ex-girlfriend’s bedroom earlier that morning.
Counsel Andy Belcher provided a letter to the court from his client, which he said was "a genuine expression of remorse".
But the judge measured that against Blunsdon’s "appalling" history.
He had previous convictions for violence, including assault with intent to injure and assault with a weapon from 2015, Judge Phillips said.
He jailed Blunsdon for two years two months and banned him from driving for a year.
A protection order was granted for the victim.