A man with an iron rod poking out of his head drove to the only open shop in a small North Island town and calmly walked up to the counter to raise the alarm.
Katikati Caltex owner Lester Gray said it was a ghoulish sight for his workers when Adam Armitage, blood streaming from the wound, came into his store early yesterday.
"It was like a Halloween prank," he said.
"It just looked like he was wearing a gruesome mask."
Armitage, 23, propping up the rod with one hand, stunned the cashier by calmly asking her if she could phone the police.
"She said, 'I think you need the ambulance not the police', and he replied, 'Okay'.
"He was amazingly relaxed," said Gray.
Several local men kept Armitage company while they waited for medics to arrive just after midnight.
"They even took photos of him on their cellphones and showed him what it looked like.
"Up until then he hadn't seen what it [the injury] was."
He said the young man was lucky his service station was open at the time as all other businesses were closed in the small Bay of Plenty township.
"I guess he's going to live because of it."
Tauranga police say the Tauranga man was sitting in his black Subaru on the side of a Katikati road when he was approached by a woman and two men.
He was punched repeatedly in the face before being struck with an iron bar which became lodged into the side of his head.
He had then driven to the service station for help.
The bar was removed at Tauranga Hospital before he was airlifted to Waikato Hospital.
Last night he was in a serious but stable condition.
Tauranga police were last night hunting for a Maori man of slim build in his early 20s with short black spiky hair.