When Jesse Frohman photographed Nirvana frontman Kurt Cobain’s last photoshoot in the summer of 1993, the singer showed up four hours late, changing the location from Central Park to a nondescript conference room at a hotel. The photographer says he thought he got maybe two good photos during 30 minutes with the singer, but instead was surprised to see he’d captured more than 100 good images that showed multiple levels of the singer’s personality. That photoshoot ended up being Cobain’s final official shoot, six months before his death. Now, Frohman is selling those images as NFTs.

An NFT, or non-fungible token, is a digital collectable that uses blockchain as a sort of certificate of authenticity. Frohman is selling the 104 image collection, called The Last Session, as a bundle with only a single edition available. The collection includes photos, contact sheets and Polaroids; Frohman says the collection includes some “never-before-seen” images of the legendary musician.

While the shoot was rushed, nearly 30 years later the photographs are considered iconic by many Cobain fans. In the images, the musician has chipped fingernail polish and dons white Jackie O sunglasses and a leopard print jacket. Retelling the story, Frohman’s website notes that Cobain arrived “in a shroud of residual catatonia” and “broke the silence by asking for a bucket—just in case.” But, Cobain’s late arrival and harried state created, as Frohman describes, an “uneasy balance” spanning from unguarded to self-destructive.

[Read: Lindsay Adler’s 10 Steps to Selling Photographs as NFTs]

The auction, however, isn’t all digital. The auction also includes one physical print of the buyer’s choice and a photo session with Frohman.

Frohman is also auctioning off a single set of 10 quadriptych NFTs from The Last Session as well as five In Utero Editions with 20 unique photographs from The Last Session.

The auction is just one more example of the exploding NFT art scene—and proof that NFTs don’t have to be newly concocted GIFs. While NFTs have been around for years selling crypto-kitties and sports collectibles, the first NFT sold by a major gallery fetched $69.3 million dollars for a single Beeple JPEG last month. That auction has arguably brought the NFT to the forefront of many artist’s minds. Selling as an NFT, however, is an investment since it does require paying fees and building a cryptocurrency wallet.

[Read: NFT Art Sales: Lindsay Adler Shares Best Practices]

The NFT auction opened today, May 3, and ends on May 7 at 6 p.m. EST. Information about the auction is available at Frohman’s website for the collection here.