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.

English singer-songwriter Dua Lipa (R) holds onto a friend in a pool in the last decade of August 2022. (Photo by dualipa/Instagram)

American gymnast Nia Dennis attends The 2021 Met Gala Celebrating In America: A Lexicon Of Fashion at Metropolitan Museum of Art on September 13, 2021 in New York City. (Photo by John Shearer/WireImage)

Manchester City's Ellen White reacts after a missed chance during the Women's UEFA Champions League match at the Academy Stadium in Manchester, United Kingdom on December 16, 2020. (Photo by Martin Rickett/PA Images via Getty Images)

American actress Kaley Cuoco goofs around for the cameras while looking fashionable filming her upcoming TV show “The Flight Attendant” in Manhattan on February 12, 2020. (Photo by LRNYC/The Mega Agency)

“Gangnam Style” star PSY's new music video had been watched more than 10 million times on YouTube less than 24 hours after he unveiled his much-anticipated new dance in Seoul, the website showed Sunday. Photo: PSY performs at his concert “Happening” in Seoul, on April 13, 2013. The South Korean pop star's first new single since his viral hit “Gangnam Style” is stealing attention from inter-Korean tensions. (Photo by Kin Cheung/Associated Press)

This is a portion of the first color 360-degree panorama from NASA's Curiosity rover, made up of thumbnails, which are small copies of higher-resolution images. The mission's destination, a mountain at the center of Gale Crater called Mount Sharp, can be seen in the distance, to the left, beginning to rise up. The mountain's summit will be imaged later. (Photo by NASA/JPL-Caltech/MSSS)