The opening of sculptor Carole Feuerman solo outdoor public art show, Sea Idylls, on Park Avenue in NYC on April 27, 2023. The hyperrealistic sculptures in conjunction with Les Galeries Bartoux and Patrons of Park Avenue line the median. (Photo by Milo Hess/ZUMA Press Wire/Rex Features/Shutterstock)

Melanie Chisholm, Emma Bunton, Melanie Brown and Geri Horner of the Spice Girls in concert at Wembley Stadium in London on Sunday, June 16, 2019. (Photo by Andrew Timms/PA Wire)

A Taliban fighter jumps into the vehicle after praying at Deh Bori square in Kabul, Afghanistan on October 18, 2021. (Photo by Zohra Bensemra/Reuters)

Transgender woman Angeles Rojas enters a room at Banco Nación where she works in Buenos Aires, Argentina, Thursday, November 5, 2020. Rojas, 23, joined the most important public bank in Argentina this year as part of the trans labor quota that is part of the public policies in favor of the LGBT community that the South American country has implemented in the last decade. (Photo by Natacha Pisarenko/AP Photo)

Social distancing signs are pictured as models wear protective face masks before the show of designer Andres Sarda during the Mercedes Benz Fashion Week amid the coronavirus disease (COVID-19) outbreak in Madrid, Spain, September 10, 2020. (Photo by Sergio Perez/Reuters)

A woman from a flood affected area arrives to receive food and other items distributed by the religious charity group Al-Khidmat Foundation Pakistan, in Shabqadar near Peshawar, Pakistan, Tuesday, September 13, 2022. The death toll from three months of record-breaking floods in Pakistan rose to over 1,400, officials said Tuesday, as the minister for climate warned the prolonged monsoon rains will continue lashing this impoverished nation in the coming weeks. (Photo by Muhammad Sajjad/AP Photo)

New York Rangers right wing Ryan Reaves punches Minnesota Wild left wing Marcus Foligno (17) during a third-period fight in an NHL hockey game Thursday, October 13, 2022, in St. Paul, Minn. (Photo by Aaroan Lavinsky/Star Tribune via AP 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.