One of Mark Rothko’s famous Seagram murals was defaced by a man at the Tate Modern on Sunday afternoon, according to multiple reports. The man tagged a name — Vladimir Umanets — accompanied by the bizarre phrase “a potential piece of yellowism” on the lower right hand corner of the 1958 canvas. The entire museum shut down for a brief period following the incident, according to the Guardian. The vandal remains at large.

The brash act of vandalism was first spotted by a lone visitor, Tim Wright, who took a picture and tweeted the news. It quickly made its way around the world. (As of this writing, Wright’s original tweet, which includes a photo of the damage, has been shared 414 times.) “We heard the sound of a pen, but by the time we turned around he was pretty much finished with his tag,” he told the Guardian.

Umanets, the suspected vandal, took responsibility for the act when reached by the Guardian. (The paper tracked him down through an online manifesto for the artistic movement “yellowism.”) Comparing himself to Marcel Duchamp, who shocked the world when he put a signed urinal on display in 1917, Umanets said he hoped his defacement would draw attention to contemporary art and shake it out of complacency. ”I believe that if someone restores the [Rothko] piece and removes my signature the value of the piece would be lower but after a few years the value will go higher because of what I did,” he told the paper.

This isn’t the first time an aspiring artist has damaged an iconic work of art. This summer, a young man named Uriel Landeros tagged a Picasso painting at the Menil Collection in Houston. In 1974, now-dealer Tony Shafrazi tagged “Guernica.” Both claimed their actions were driven by a desire to wrest art from fossilized, out-of-touch history and give it new life.

The museum confirmed the vandalism in a statement to the press earlier today. “Tate can confirm that there was an incident in which a visitor defaced one of Rothko’s Seagram murals by applying a small area of black paint with a brush to the painting,” a Tate spokesperson said.

The Seagram murals were originally intended for the walls of New York’s Four Seasons restaurant, but they were never installed. Rothko himself presented a number of the murals to the Tate as a gift shortly before his death in 1970. This year, they were given pride of place in a new gallery, the Rothko Room. Shortly after the re-hang, critic Jonathan Jones wrote, “So long as Tate Modern displays these paintings, they will blaze bright and dark as masterpieces that shudder the world.”

“The Rothko family is greatly troubled by yesterday's occurrence but has full confidence that the Tate Gallery will do all in its power to remedy the situation,”said Kate Rothko Prizel and Christopher Rothko in a statement released by Pace Gallery. “Our father donated his legendary Seagram paintings to the museum in 1969 sensing the commitment of the institution to his work and impressed by the warm embrace it had received from the British public. We are heartened to have felt that embrace again in the outpouring of distress and support that we and our father have received both directly and in public forums.”

Stay tuned for more updates. It seems this story is only going to get stranger. As an eagle-eyed observer pointed out on Twitter, the vandal’s supposed name, Vladimir Umanets, is an anagram of the phrase “I’m True Vandalism.”