Drawing inspiration from people, humanoid robot Sophia has created a digital artwork in the form of a nonfungible token (NFT). The work fetched $688,888 at a Hong Kong auction on Thursday.

NFTs, a digital signature saved on blockchain ledgers that allow anyone to verify the ownership and authenticity of items, have become the latest investment craze. A digital collage artwork by Beeple even sold this month for nearly $70 million.

Humanoid robot Sophia, who was unveiled in 2016, produced her art in collaboration with 31-year-old Italian digital artist Andrea Bonaceto, known for colorful portraits, some of which depict famous people, such as Tesla's chief executive, Elon Musk.

The robot has combined elements from Bonaceto's works, art history and her own physical drawings or paintings on various surfaces multiple times, in a process her creator David Hanson describes as "iterative loops of evolution."

Titled "Sophia Instantiation," the digital work is a 12-second MP4 file showing the evolution of Bonaceto's portrait into Sophia's digital painting and is accompanied by a physical artwork, painted by Sophia on a printout of her self-portrait.