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 man sits on top of a car as he is stranded on a flooded street in Tianjin, China, July 20, 2016. (Photo by Reuters/Stringer)

Three cabaret dancers sit glum-faced in the Windmill Theatre's canteen upon hearing the news that the theatre's owners have sold out to a cinema company, on October 02, 1964. The theatre, which was the first to include nudity in its shows, has been able to cope with competition from a growing number of West End strip clubs. (Photo by Hulton-Deutsch Collection/CORBIS/Corbis via Getty Images)

A herd of elephants cross a road that passes through the flooded Kaziranga National Park in the northeastern state of Assam, India, July 12, 2017. (Photo by Anuwar Hazarika/Reuters)

Revellers of street parties known as blocos, dance during a protest against restrictions by city officials in Rio de Janeiro, Brazil, Wednesday, April 13, 2022. City Hall has banned the street parties during Carnival celebrations, which were delayed by almost two months due to the pandemic. (Photo by Silvia Izquierdo/AP Photo)

A person takes photos of Vervet monkeys that are eating in a parking lot near the Fort Lauderdale-Hollywood International Airport in Dania Beach, Florida, USA, 10 May 2022. Over 40 descendants of smallish vervets, escaped from now closed breeding facility, are living within 1,500 acres around the Fort Lauderdale-Hollywood International airport. The Dania Beach Vervet Project is an organization established in 2016 with the purpose of promote the conservation, and education about the local free ranging vervet monkeys in Dania Beach, Florida. (Photo by Cristóbal Herrera/EPA/EFE)

Australian professional boxer Ebanie Bridges at the weigh-in ahead of their IBF World Bantamweight Title fight against Shannon O'Connell during the weigh in at Aspire, Leeds, United Kingdom on Friday, December 9, 2022. (Photo by Tim Goode/PA Wire)

A participant rests while people take part in the Mermaid Parade at Coney Island, in Brooklyn, New York, June 20, 2015. The annual parade, founded in 1983, seeks to bring mythology to life for residents, create confidence in the district and to allow artistic self-expression in public, according to the parade's website. (Photo by Eduardo Munoz/Reuters)