People in funny costumes race down the slope in bathtubs during the 7th Bathtub race at Stoos, Switzerland, on January 19, 2019. (Photo by Urs Flueeler/EPA/EFE/Rex Features/Shutterstock)

Early morning storms over the Masai Mara National Reserve, Kenya on August 26, 2016. (Photo by Action Press/Rex Features/Shutterstock)

A worker sprays disinfectant as sanitization operations against Coronavirus are carried out in the museum hosted by the Maschio Angioino medieval castle, in Naples, Italy, Tuesday, March 10, 2020. (Photo by Alessandro Pone/LaPresse via AP Photo)

A man designs a face mask with the photograph of a customer printed on it, amid the spread of the coronavirus disease (COVID-19), at a photo studio in Gandhinagar, India, May 27, 2020. (Photo by Amit Dave/Reuters)

A reveller helps a woman prepare her costume after the normal Notting Hill Carnival festivities were cancelled for a second year running, amid the coronavirus disease (COVID-19) outbreak, in London, Britain, August 30, 2021. (Photo by Beresford Hodge/Reuters)

A man bathes at a roadside in a market area after authorities in the capital ordered a weekend curfew, following the rise in the coronavirus disease (COVID-19) cases, in the old quarters of Delhi, India, January 8, 2022. (Photo by Adnan Abidi/Reuters)

A person looks at Australian artist Ron Muecks large-scale installation “Mass” which comprises more than 100 hand-cast skulls that collectively weigh approximately 5000 kilograms at an exhibition at the National Gallery of Victoria (NGV) in Melbourne on May 18, 2022. (Photo by William West/AFP Photo)

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.