Mark Robert Williams, 44, faces court after allegedly threatening to bomb suburban McDonalds

A man who allegedly threatened to “bomb everyone” inside an Adelaide McDonald’s returned to use the self-serve menu, a court has heard.

A man who allegedly threatened to bomb a northern suburbs McDonalds and its customers could not have been serious – because he returned for a hamburger, a court has heard.

Mark Robert Williams appeared in the Elizabeth Magistrates Court via video on Tuesday after being arrested at the McDonalds at the Saints Road Shopping Centre on Wednesday night.

Opposing bail, prosecutors alleged Mr Williams told customers he was going to bomb “everyone” inside the Salisbury Plains restaurant.

“He was seen to be acting erratically, causing concern to other customers and he then was heard to say, ‘I am going to bomb this place, I am going to bomb everyone in here’,” police prosecutors alleged.

The court heard Mr Williams, of Parafield Gardens, then ran from the restaurant, leaving behind a backpack.

A man is arrested outside the McDonald’s after the alleged bomb hoax. Picture: 7NEWS Adelaide

Bomb squad officers sweep the Macca’s. Picture: 7NEWS Adelaide

But after staff notified police and evacuated the restaurant, he returned, and began to make an order at a self-service screen, the court heard.

“The behaviour is rather odd, if he was intending to make a threat Your Honour, why would he then return to the store and order a hamburger?” counsel for Mr Williams said.

“It seems odd that there would be any deliberate malicious intent.”

The 44-year-old is yet to enter a plea to one count of creating a false belief that life has been lost or endangered.

Police responded to the restaurant about 7.45pm after reports a man left a bag inside claiming it contained a bomb.

Police outside the Salisbury Plains McDonald’s. Picture: 7NEWS Adelaide

Employees and customers were evacuated from the McDonald’s on Saints Rd and patrols quickly detained the man.

Technicians from the Bomb Response Unit attended and determined no explosives were inside the bag.

He was refused police bail and will appear in the Elizabeth Magistrates Court on Thursday.

Police said there were no reports of injuries, and emergency services stayed on the scene for several hours.

On Thursday, counsel for Mr Williams submitted their client had an acquired brain injury and was living in NDIS-funded accommodation.

The court heard drugs were a factor.

A bag is removed from the Macca’s. Picture: 7NEWS Adelaide

During the hearing, Mr Williams continued to speak out, and was muted.

Prosecutors submitted Mr Williams had recently been sentenced for a number of theft matters, was on supervised bail at the time of the alleged offending and had a history of breaching court orders.

Counsel for Mr Williams said while it was a potentially scary experience for the restaurant customers and staff, the alleged conduct was not legislatively at the higher end of seriousness.

Magistrate Lana Chester remanded Mr Williams in custody pending a bail inquiry and a home detention report.

He will return to court later this month.

Originally published as Mark Robert Williams, 44, faces court after allegedly threatening to bomb suburban McDonalds