A man who took a ukulele from an Adelaide Fringe performer and allegedly bashed him over the head with it has been described in court as a "menace" with a significant history of violence.

Key points: Barry Phillip Siecker was refused bail in the Adelaide Magistrates Court

Barry Phillip Siecker was refused bail in the Adelaide Magistrates Court Prosecutors said he has a "propensity towards violence"

Prosecutors said he has a "propensity towards violence" The court heard Mr Siecker as a methamphetamine dependence

Barry Phillip Siecker, 29, appeared in the Adelaide Magistrates Court today charged with aggravated assault over the alleged attack against Matt Eberhart at Rundle Mall — which took place in front of shocked onlookers.

The court was told Mr Siecker took issue with the busker, who performs under the name Banana Man and was wearing a pencil costume, and "deemed comments to an Asian female as racist and inappropriate".

Opposing bail, police prosecutors told the court that the incident was filmed by members of the public who were gathered at Rundle Mall to watch the busker about lunchtime on Wednesday.

"In an unprovoked fashion, he took the ukulele off him and smashed it on the floor," he said.

"He also assaulted the victim and hit him on the head, causing two quite significant gashes along his forehead.

"The defendant has a significant criminal history that is littered with violence.

"Notably, the defendant was sentenced to two months' imprisonment on June 29, 2019, for an aggravated assault.

He said Mr Siecker had a "propensity towards violence".

Prosecutors describe the accused as a 'menace'

"The defendant is currently standing trial in April this year, and he's on bail for that trial … which is also for an aggravated assault," he said.

"Your Honour, he's clearly a menace, he clearly has a propensity for violence — his history is littered with it.

The Fringe artist was allegedly bashed in Rundle Mall. ( ABC News )

"It was an unprovoked attack on a member of the public.

"It was completely unacceptable.

"He's committed that act while on bail pending trial for serious violent offending.

"It would be a real danger to the public to release this individual on any form of bail.

"He's an extremely poor candidate for bail."

The court heard the accused had a methamphetamine dependence, self-reported borderline personality disorder traits and has presented to hospital with symptoms of psychosis.

'Accused was offended by the skit'

But counsel for Mr Siecker told the court her client became offended by the performer's skit.

"This skit is about singing and picking members of the public out and addressing them, talking about them, through his song," she said.

"The [alleged victim] has made a comment which Mr Siecker found to be racist and abusive to a member of the public."

She said he approached the Fringe performer and picked up his ukulele to "grab his attention" but he perceived the victim to "come at him" and has responded by allegedly attacking him.

"He deemed the comments to an Asian female as racist and inappropriate," she said.

Magistrate David McLeod refused Mr Siecker's application for bail, and adjourned the case until next week.