Demonstrators dance around a burning an effigy of the Russian President Vladimir Putin during an anti-war action in Tbilisi, Georgia, Sunday, March 27, 2022. (Photo by AP Photo/Stringer)

Light painting on the beach at Walton-on-the-Naze in Essex, United Kingdom on April 25, 2023 using burning steel wool spun around on a rope sending sparks flying. (Photo by Kevin Jay/Picture Exclusive)

A policeman stands by a burning car, set alight during a communist march in the East End of London. (Photo by Topical Press Agency/Getty Images). Circa 1936

Canadian actress Nina Dobrev kicks her leg up at Burning Man in the first decade of September 2022. (Photo by nina/Instagram)

An emu runs to escape an approaching wildfire as it burns near Potero, California, U.S. June 20, 2016. (Photo by Mike Blake/Reuters)

A protester gestures as he holds a dog before a burning barricade during protests in Harare, Zimbabwe on January 15, 2019. (Photo by Philimon Bulawayo/Reuters)

Fire retardant is dropped on the Fairview Fire burning near Hemet, California, U.S., September 6, 2022. (Photo by David Swanson/Reuters)

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.