Blankets cover the bodies of a woman (right) and a man (left background) hit by a northbound Penn Central train (background) as they waited with a crowd at Pennsylvania Railroad station in Elizabeth, N.J. on June 8, 1968 to view the southbound train carrying the body of Sen. Robert F. Kennedy to Washington. The woman was identified as Mrs. Antoinette Severini, 54, and the man, John Curia (age unavailable), both of Elizabeth. (Photo by AP Photo)

A cat, named “Sulo”, is seen in Istanbul's Sultanahmet Square wearing sunglasses, in Turkiye, on December 30, 2022. (Photo by Murat Sengul/Anadolu Agency via Getty Images)

Andrey Rublev shouts at line judge while playing against Alexander Bublik of Kazakhstan in their semifinal match during the Dubai Duty Free Tennis Championships at Dubai Duty Free Tennis Stadium on March 01, 2024 in Dubai, United Arab Emirates. (Photo by Christopher Pike/Getty Images)

The moon is seen in its waxing gibbous stage as it rises behind the helicopter from the original Batman television show, which people can ride at the New Jersey State Fair, Saturday, June 22, 2013, in East Rutherford, N.J. The moon, which will reach its full stage on Sunday, is expected to be 13.5 percent closer to earth during a phenomenon known as supermoon. (Photo by Julio Cortez/AP Photo)

Models wait backstage during the Ukrainian Fashion Week in Kiev, October 16, 2015. (Photo by Valentyn Ogirenko/Reuters)

Pascal Martinot-Lagarde, of France, celebrates his bronze medal in the men's 110 meter hurdles final at the World Athletics Championships in Doha, Qatar, Wednesday, October 2, 2019. (Photo by Petr David Josek/AP Photo)

Julia Marino of USA in action during the final run of the snowboard slopestyle competition at the Laax Open, in Laax, Switzerland, 17 January 2020. (Photo by Gian Ehrenzeller/EPA/EFE/Rex Features/Shutterstock)

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.