(CNN) -- The elusive graffiti artist Banksy made his mark on a painting bought for just $50 from a New York City thrift store, and bidding has exceeded $300,000 in a charity auction.
The painting, which the famously anonymous British graffiti artist entitled "The Banality of the Banality of Evil," is being auctioned off to benefit Housing Works, a nonprofit that supports homelessness and those living or affected with HIV/AIDS, according to spokeswoman Rebecca Edmondson.
The painting was dropped off at the store in New York's Gramercy area by an anonymous person on Tuesday.
"The painting came in as secretly as we could have anticipated based on Banksy's reputation," Edmondson said, "Our retailer that was working was told it was special and given a little note."
According to Housing Works, the painting was purchased from the same shop a couple months ago for $50. The charity has thrift shops across New York City that help fund the services they provide.
"A thrift store painting vandalized then re-donated to the thrift store," Banksy described on his website.
"There was definitely a plan in place," Edmondson said.
The painting is now being auctioned on Bidding For Good, a platform for online and mobile auctions. The painting went up for online auction on October 29 with a starting minimum bid of $74,000.
Bidding will end at 8 p.m. on October 31.
Known for his signature street-art style of stencils spray-painted on streets, walls, and under bridges, Banksy brought a new element to his work with this oil on canvas.
The painting depicts a countryside landscape featuring a large lake, trees with autumn colors, and snowy mountains in the background. The one outlier is an officer on a bench in the foreground with what appears to be a Nazi symbol stitched to his right sleeve.
Banksy has stirred some controversy in New York City during his month-long street-art residency, "Better Out Than In." He angered New Yorkers most recently with his critique of the One World Trade Center design.
Housing Works, however, is not judging the meaning behind his work.
"Banksy is giving back to the New York community that has watched his every move over the last month," Edmondson said, "Nothing but good could come of it."
Housing Works was contacted by Banksy's team to confirm the donation and authenticate the painting signed by Banksy under the original artist, K. Sager.
"They were pretty straightforward," Edmondson said, "We were given permission to auction it off."
Edmonson estimates that the auction will pull in $1 million.
Banksy debuted the latest addition to his New York City art collection on Wednesday with "Bronx Zoo," a graffiti painting of a growling wild cat resting on a railing, outside of Yankee Stadium, according to his website.
CNN's Rande Iaboni contributed to this report.