If we were to burn NH4Cr2O7 with HgSCN in the Dark Ages in Europe and show it to anyone, it is us who would be burning next on a fiery cross of Inquisition. And it’s no wonder, since this experiment produces a truly marvelous result. At first, as you ignite the mixture of NH4Cr2O7 and HgSCN, all you can see is that it is slowly burning with a reddish flame. After a while, however, a crater is formed in the middle of the burning pile, and then, suddenly, tentacle-like appendages start sprouting from the burning mixture. And you can almost hear the scream of the mad occultist – “Come forth, Kraken! Come forth!” But of course, this is simply a chemical reaction that is called the "Pharoah's Serpent". It was also often sold in firework stores until people realized that it was toxic.

Ron Mueck's “Big Baby” sculpture appears to look round at Jenny Saville's painting “Interfacing” at the Masterpieces Exhibition at Christie's on June 13, 2011 in London, England. The painting and sculpture feature in the exhibition, open to the public from 13th–15th June 2011, which showcases some of the Ј250 million worth of art for sale over the next four weeks. Artists including Michelangelo, Gainsborough, Goya, Stubbs, Monet, Picasso and Renoir are represented. (Photo by Peter Macdiarmid/Getty Images)

A Jennie fan waits in the crowd for Jennie's perform at the Coachella Valley Music and Arts Festival in Indio, California, U.S., April 13, 2025. (Photo by Daniel Cole/Reuters)

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English actress Florence Pugh celebrates her 26th birthday in the “best f--king party shoe” on January 3, 2022. (Photo by Instagram/Florence Pugh)

The Big Island's Mauna Loa Volcano erupts on November 28, 2022 on the Island of Hawaii. For the first time in almost 40 years, the biggest active volcano in the world erupted prompting an emergency response on the Big Island. (Photo by Andrew Richard Hara/Getty Images)

These stunning sand sculptures are being used to encourage youngsters to explore their surroundings and play in the dirt. (Photo by OMO Lowe)