The world-renowned Art Basel Miami Beach art show is a regular gathering for celebrity art patrons. But confusion struck the upscale exhibit on Friday night when visitors observed a woman being stabbed and thought the violent attack was part of a performance art routine.

Miami Beach Detective Kathleen Prieto told the Miami Herald that a woman pulled out an X-Acto knife and stabbed another woman in the arms and neck during the event.

Police said the incident occurred after the victim confronted suspect Siyuan Zhao, who had been following her around the art show and bumping into her. Zhao then allegedly stabbed the victim.

The Herald reports that some patrons thought the stabbing was a performance art presentation, but the blood they saw was real.

The attack happened near an exhibit by Miami artist Naomi Fisher and her partner Agatha Wara.

Fisher told the paper, “A guy walked up to me and said, ‘I thought I saw a performance, and I thought it was fake blood, but it was real blood.’”

“It’s horrible,” Fisher said. “I’m so freaked out. I feel nauseous.”

The champagne-sipping art patrons were shocked by the event, according to the Herald:

Gregg Hill, a sculptor visiting from New York, said he saw the victim being wheeled out on a gurney but never suspected she was the victim of a violent act.

“I thought a piece of art fell on her,” he said. “I never would have thought there would be a stabbing at Art Basel.

Other visitors reportedly believed the police tape cordoning off the crime scene was part of an art installation.

The stabbing victim was taken to an area hospital where she was treated for non-life threatening injuries. Her attacker was arrested at the scene and has since been charged with felony attempted murder.

In a statement about the incident, Art Basel’s spokeswoman Sara Fitzmaurice wrote: “The attack was an isolated incident that was immediately secured. The suspect was apprehended by police who were at the scene within seconds of the incident…. Our thoughts are with the victim.”