A runner competes in the Great Wall Marathon at the Huangyaguan Great Wall outside Beijing, China, May 18, 2019. (Photo by Thomas Peter/Reuters)

Morocco's Romain Saiss, right, reacts after teammate Abdelhamid Sabiri, not visible, scored a goal on Belgium's goalkeeper Thibaut Courtois, left, during the World Cup group F soccer match between Belgium and Morocco, at the Al Thumama Stadium in Doha, Qatar, Sunday, November 27, 2022. (Photo by Frank Augstein/AP Photo)

A girl peers from between light decorations at a Christmas fair which opened ahead of the holiday season in Bucharest, Romania, Friday, November 25, 2022. Municipal authorities in the Romanian capital, quoted by local media, stated that holiday season city light decoration levels will remain at last year's level and use energy saving solutions. (Photo by Vadim Ghirda/AP Photo)

Manchester City's Belgian midfielder #11 Jeremy Doku eyes the ball during the UEFA Champions League quarter-final second-leg football match between Manchester City and Real Madrid, at the Etihad Stadium, in Manchester, north-west England, on April 17, 2024. (Photo by Paul Ellis/AFP Photo)

Julian Ryerson of Borussia Dortmund during the Bundesliga match between Borussia Dortmund and 1. FC Union Berlin at Signal Iduna Park on April 8, 2023 in Dortmund, Germany. (Photo by Alexandre Simoes/Borussia Dortmund via Getty Images)

Lamon Reccord, right, stares and yells at a Chicago police officer "Shoot me 16 times" as he and others march through Chicago's Loop Wednesday, November 25, 2015, one day after murder charges were brought against police officer Jason Van Dyke in the killing of 17-year-old Laquan McDonald. (Photo by Charles Rex Arbogast/AP Photo)

Elena Reid of USA looks on with bloody face due to a cut during the Women's WIBF Flyweight Championship fight between Regina Halmich and Elena Reid at the Boerderlandhalle on December 3, 2005 in Magdeburg, Germany. (Photo by Christian Fischer/Getty Images)

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.