Written by Mirna Alsharif, CNN New York

The walls of most bars are adorned with artwork of some kind, including the doodles of patrons after a few drinks. But a Manhattan bar has a set of doodles that could be worth hundreds of thousands of dollars.

The doodles are the creation of Japanese artist Yoshitomo Nara, who took a felt-tip pen 10 years ago to the walls of Niagara , a bar he frequents in the city's East Village neighborhood. Nara's painting, "Knife Behind Back," sold for $24.9 million at Sotheby's Hong Kong last weekend and now his decade-old drawings could be worth hundreds of thousands of dollars, according to a Sotheby's representative.

"Knife Behind Back" by Yoshitomo Nara recently sold for $24.9 million. Credit: Yoshitomo Nara/Blum & Poe, Los Angeles/New York/Tokyo

Tim Blum, an artist manager who has represented Nara since 1994, say he was with Nara in 2009 at the bar. Blum says they were out to celebrate following the stress of putting a show together. After a few drinks, Nara pulled out a felt-tip pen.

"He took a pen to the wall and everyone was kind of into it. It was a blur at the time because no one was thinking we should remember this 10 years later," said Blum, adding that the "capper of the night" was Nara's arrest by the NYPD after he drew graffiti at a subway station.

And take a pen to the wall he did. The result? A wall mural of Nara-esque figures right across from the bar counter. The figure closest to the door can be seen dancing with a speech bubble reading "Hey! Ho! Let's Go!" The phrase is a nod to the opening line of "Blitzkrieg Bop" by quintessential New York punk band The Ramones.

To the right there are two more figures; one playing guitar while another is on drums.

By the exit sign is the lead singer of the band Nara created. His message to Niagara bar crawlers? "Hey NYC Are You Happy?"

But that's not all. Nara drew a girl by the women's bathroom and a boy by the men's bathroom, welcoming all the "cool" girls and boys to Niagara's lavatories.

Nara's doodle of a "typical bass player." Credit: Courtesy Thom Bennett

"It's very typical Nara," Blum said of the drawings. "They're very music-oriented figures, he was inspired by the bar's music for sure."

One look at Nara's work and spectators can see the similarities between the East Village doodles and his paintings. For example, "One Foot in the Groove" — which sold for $1.16 million — contains a figure with similar hair, limbs and dress as those seen in the bar.

But unlike Nara's paintings, the drawings at the East Village bar were very low-key, only landing on the radar of art enthusiasts' after his record-breaking sale.

Jennifer Convery-Masser had no idea this doodle was drawn by a famous artist when she photographed it in 2016. "It was unsigned & I love it!" she told CNN over Instagram. Credit: Jennifer Convery-Masser

So how does this drawing stack up to his million-dollar paintings?

"The imagery itself is quite in keeping with his style," said David Schrader, head of private sales at Sotheby's. "My guess is it's probably worth hundreds of thousands. For sure, when an artist gets a record-selling price, it elevates them in the market. My gut is there are definitely people who would want to own this or the multiple pieces individually."

However, Schrader said that the drawings' lack of certification and that they are not included in Nara's professional portfolio would affect pricing.

"It's helpful to know that people were there to see that he did create it and that he signed it, but Nara's most desirable works are big figures on canvas. As you go down in materials used, you'll have a pretty big decline in value," Schrader said, adding that this art is site specific and "wasn't meant to be sold."

The Niagara's management declined to comment, but a bartender told CNN that the artwork "has been a part of the bar for a long time and will stay that way." The drawings are safeguarded by a thin layer of plastic that was installed by the bar's ownership.

Nara doesn't want to see the drawing sold, according to Blum.

"It was done in the spirit of the moment," Blum said. "Nara isn't interested in any kind of monetarization discussion, but it's certainly worth some money."