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.

A model presents a creation by Italian designer Donatella Versace as part of her Haute Couture Fall/Winter 2016/2017 fashion show for Atelier Versace in Paris January 24, 2016. (Photo by Gonzalo Fuentes/Reuters)

Bella Thorne is seen in Soho on September 10, 2017 in New York City. (Photo by Splash News and Pictures)

Former top models Carla Bruni (L), Claudia Schiffer, Naomi Campbell, Cindy Crawford and Helena Christensen display iconic creations of late Italian designer Gianni Versace's during the Versace Spring/Summer 2018 show at the Milan Fashion Week in Milan, Italy, September 22, 2017. (Photo by Stefano Rellandini/Reuters)

American media personality Draya Michele attends #REVOLVEawards at DREAM Hollywood on November 2, 2017 in Hollywood, California. (Photo by Barry King/Getty Images)

Nikolai Vasilyev, 64, dressed as Father Frost, the Russian equivalent of Santa Claus, water-skis along the Yenisei River outside the Siberian city of Krasnoyarsk, Russia December 19, 2017. Vasilyev, former teacher of the Siberian State Aerospace University, constructed the water skis out of plastic foam and designed the sticks to propel him forward, while travelling on the water surface. (Photo by Ilya Naymushin/Reuters)

In this image released on November 08, American singer Madison Beer poses at the MTV EMA's 2020 on October 30, 2020 in Los Angeles, California. The MTV EMA's aired on November 08, 2020. (Photo by Rich Fury/Getty Images for MTV)

In this image released on December 09, English model Leomie Anderson and English model and actress Jourdan Dunn attend the 2020 MOBO Awards held at Exhibition London on December 07, 2020 in London, England. The MOBO Awards will be live-streamed on YouTube at 7pm and broadcast on BBC One at 10.45pm. (Photo by Michael Tubes/MOBO Organisation/Rex Features/Shutterstock)