"At first I thought it was just fun and games and then as soon as I got a sniff of the petrol I freaked out."
Hayden described the pain as "unimaginable".
"It lit up the room and all I could see were shadows of people laughing at me, no one came to help except one of my friends who helped pat out the fire as I ran out the door," he said. "It took me about 10 minutes to bike home. The shirt had been burned on to my skin, so when I ripped it off it tore my back off too."
Arriving home to a horrified mother, Hayden could only muster the words "they burnt me, petrol".
"My mum shoved me straight in the shower. I remember the cold water was so painful. When the ambulance came all my veins had collapsed and they had to insert the IV between my toes.
"I could feel every bump in the road on the way to the hospital, it was the worst pain ever. It felt like someone was cutting you up with a knife."
Today Hayden lives with the memories from the months of recovery, the emotional torture of Shannon's court trial but ultimately a strength that saw him through the nightmares.
"I got pretty depressed for a long time but time has helped give me closure."
Shannon was sentenced at the High Court in Napier for his role in the attack and found guilty of causing grievous bodily harm with intent.
His prison term was reduced to three years due to his age, 17 at the time, and for his assistance in helping police identify the other attackers.
"I was getting two hours' sleep a night and it was driving me insane," Hayden said of the trial. "When the detective, Mark Moorhouse, rang me and said he was guilty I burst into tears, but I wasn't crying because I was sad, I was crying because it was a relief, a sense of closure. I felt safer and I could sleep again."
He said Shannon wrote him a letter from prison trying to apologise but blamed alcohol for his unforgivable acts.
"I'll never forgive him. I don't want to see him ever again. People know right from wrong," Hayden said.
The reduced sentence upset him but he accepted there was nothing he could do and said it was "better than nothing, it stopped him walking free".
"I think he [Shannon] goes up for parole in September, so I will probably start feeling anxious again then and when he gets out."
It took six months for Hayden's back and neck to begin showing signs of normality after doctors said he had lost 30 per cent of the skin in the area.
"Every time I thought about it I would curl into a little ball and cry. I was nervous about people judging me with my scars."
Time with a psychologist and writing music and poetry helped his road to recovery, while he expressed his anger and emotions with karate training every day.
"It's still hard to process though. I can't be in big groups of people, I don't go out to the pub or anything cause then I just start to feel anxious.
"Parts of it [incident] I still blame myself for and I tried to suppress it for awhile. I learned that was not the way to handle things, I had to open up."
He urged anyone who found themselves in similar emotional pain to reach out for help and know something better will come.
"I want to know why it happened, why me and that is something I want to know to give me full closure one day."
Currently working at an orchard, Hayden is now a qualified computer technician and aims to move to Australia and begin a career. "I'm looking forward to the future, my mum was always there for me and I feel like there's love for me now. I'm just so thankful to still be alive."
