NEW YORK (AP) — When the enigmatic street artist Banksy spray-painted a heart-shaped balloon covered with a Band-Aid on the wall of a Brooklyn warehouse, the nondescript brick building was instantly transformed into an art destination and the canvas of an unlikely graffiti battle.

Almost as soon as Banksy revealed the piece back in 2013, an anonymous tagger brazenly walked up and spray painted the words “Omar NYC” in red beside the balloon, to the dismay of onlookers.

Days later, someone stenciled “is a little girl” in white and pink beside Omar’s tag, followed by a seemingly sarcastic phrase in black: “I remember MY first tag.” Some think it was Banksy himself who secretly returned to the scene to add the rejoinder.

The apparent graffiti battle didn’t end there. Another tagger also attempted to leave his mark but was stymied by security guards. Today the phrase “SHAN” is still visible in light purple paint.

Maria Georgiadis, whose family owned the now-demolished warehouse and ultimately removed the section of wall to preserve the artwork, says the graffiti pastiche is quintessentially New York.

“It looks like a war going on,” she said recently. “They’re literally going at it on the wall.”

The preserved wall, dubbed “Battle to Survive a Broken Heart,” will be going up for sale May 21 at Guernsey’s, the New York auction house.

Georgiadis, a Brooklyn schoolteacher, says the sale is bittersweet. Her father, Vassilios Georgiadis, ran his roofing and asbestos abatement company from the warehouse adorned with the balloon.

He died four years ago at age 67 from a heart attack, which is why some of the proceeds from the sale will be donated to the American Heart Association.

“It’s just very significant to us because he loved it and he was just so full of love,” Maria Georgiadis said on a recent visit to the art warehouse where the piece was stored for more than a decade. “It’s like the bandage heart. We all have love, but we’ve all went through things and we just put a little Band-Aid over and just keep on moving, right? That’s how I take it.”

The nearly 4-ton, 6-foot-tall wall section is one of a number of guerrilla works the famously secretive British artist made during a New York residency in 2013.

At the time, Banksy heralded the work by posting on his website photos and an audio track recorded partly in a squeaky, helium-induced voice.

Guernsey auction house President Arlan Ettinger said it is impossible to know for certain because Banksy works clandestinely. But he said the neat stenciling and wording “strongly suggest that this was a gentle way for Banksy to put the other artist in his place.”