A man was left with a ruptured left ear drum and a scalp laceration that required gluing to heal after a vicious jail bashing last year.
The man responsible, 20-year-old Dylan Winters, was sentenced to three years and six months in prison on Monday for the assault and an earlier armed robbery at the Isabella Plains IGA.
He eventually pleaded guilty to both offences.
Winters had gone to the IGA one night in January last year armed with a machete. He was with a co-offender who was armed with a kitchen knife.
They demanded money and cigarettes from the cashier and made off with $3046.
Later that year, in May, while Winters was being detained in the Alexander Maconochie Centre, he approached another inmate from behind and unleashed a violent assault.
Winters rained down between 15 and 20 blows on the man's face and head causing him to bleed. When the victim fell to the ground, Winters kicked him in the face and ribs and stomped on his head several times.
The man was left with swelling and abrasions to his head, a ruptured ear drum and a T-shaped laceration on his head that had to be glued.
The court received a victim impact statement from the IGA cashier who reported becoming hypervigilant when he was on shift after the attack. His mother also told the court that her son had become depressed after the robbery and received counselling.
The court heard Winters was using the drug ice daily prior to committing the aggravated robbery and had been on a suspended prison sentence with a good behaviour order.
A report noted Winters' behaviour while on remand had been poor, he received a number of warnings and penalties for inappropriate behaviour during visits, verbally abusing custodial officers, threats of violence and meal tampering.
Winters' lawyer told the court the robbery was unsophisticated but included elements of planning but pointed out there was no assault on the cashier and no direct threats of harm.
Winters told the author of a pre-sentence report that "nobody should ever have to go to work and have to worry about being robbed".
"I'm very sorry for how I have made them feel," he said.
He also accepted responsibility for the prison assault and did not try to minimise his actions, Justice Chrissa Loukas-Karlsson determined.
Winters has been diagnosed with Intermittent Explosive Disorder and Aggressive Conduct Disorder.
Justice Loukas-Karlsson sentenced Winters to three years and six months prison with a non-parole period of two years and two months. He will be eligible for release in December 2020.