To create the piece, Chinneck trapped a five-metre-tall Christmas tree inside a two-tonne block of resin carved to look like an ice cube.
A surrounding puddle, which looks as if it is melting into the ground-level fountain, is actually made from 250 kilograms of clear wax.
At night, 1,200 lights adorning the tree glow brightly through the resin.
Chinneck, who specialises in architectural installations featuring optical illusions, was also the artist behind a house in Margate with a slumping brick facade and a levitating building in Covent Garden's Piazza.
"King's Cross is known for its quirky installation, and I wanted to build on this," Chinneck told Dezeen. "Everything we produce is unique to us, and we want the people who are experiencing it to have the same feeling."
"We try to set ourselves problems that only technical exploration can solve. I was thinking about a seasonally relevant material and landed on the idea, like a fly-in-an-ice-cube."
The Fighting Fire with Ice Cream installation will be up in Kings Cross until 6 January 2017.
Other designer festivities taking place across the capital include an upside-down Christmas tree suspended from the ceiling of Tate Britain, and an immersive Christmas tree installation by Apple's Jonathan Ive and industrial designer Marc Newson.
Photography is by Iwona Pinkowicz.