Deadpool, the mouthy mercenary producing big box-office sales, may soon set a record at a comic-book auction. Cover artwork featuring Deadpool's first appearance in the comics went on sale this week at Heritage Auctions with an asking price of $7.5 million. If it sells at that price, it will be the most valuable comic-book art ever sold.

The pencilled artwork was created by writer/artist Rob Liefeld, at age 23, for New Mutants #98, which was released in February 1991. Liefeld does not own the artwork. He sold it to a collector 25 years ago, although he said he is thrilled that the character he created is doing so well financially.

"I just keep smiling," said Liefeld about the auction.

Ryan Reynolds plays Deadpool in the box-office hit Deadpool & Wolverine, a movie from Walt Disney-owned Marvel Studios. The film ranks as the highest-grossing R-rated movie of all time with more than $879 million in global ticket sales. When New Mutants #98 was released in 1991, the comic book cost $1. Now the original editions have become one of the most sought-after comics for collectors, with issues selling from $350 to $55,000 on eBay.

"Selling artwork was part of the income stream back then," Liefeld told Reuters. "I sold this 25 years ago. I have zero regrets."

Liefeld created Deadpool as a combination between Spider-Man and G.I. Joe. Immediately after his first appearance, Marvel Comics was flooded with fan mail.

"Marvel contacted me and said, this is the most fan mail we've had on a new character in 15 years," said Liefeld. "They were flooded with letters, fan letters, which they sent me. And the box that that mail arrived in ... I thought I was getting a washer and dryer," he joked.

The current record holder in comic-book auctions is a copy of Action Comics #1, which features the first appearance of Superman and sold for $6 million earlier in the year, also at Heritage Auctions.

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