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 protester gestures as he holds a dog before a burning barricade during protests in Harare, Zimbabwe on January 15, 2019. (Photo by Philimon Bulawayo/Reuters)

Fire retardant is dropped on the Fairview Fire burning near Hemet, California, U.S., September 6, 2022. (Photo by David Swanson/Reuters)

Flames burn in a field in Capaci, near Palermo, in Sicily, southern Italy, Wednesday, July 26, 2023. On the island of Sicily, two people were found dead Tuesday in a home burned by a wildfire that temporarily shut down Palermo's international airport, according to Italian news reports. Regional officials said 55 fires were active on Sicily, amid temperatures in the 40s Celsius. (Photo by Alberto Lo Bianco/LaPresse via AP Photo)

Satirical sculptures burn during the traditional Fallas festival in Valencia, Spain, on March 19, 2014. Every year the city celebrates the ancient “Las Fallas” fiesta, a noisy week that is full of fireworks and processions in honor of Saint Joseph that ends on midnight of March 19, burning large satiric figures displayed around the streets of the city. (Photo by Alberto Saiz/Associated Press)

Mazouza Bouglada, 86, a berber woman from the Chaouia region, who has facial tattoos, poses for a photograph in Taghit in the Aures Mountain, Algeria October 8, 2015. Bouglada was tattooed aged 7 by a nomadic man from the Sahara region. She was advised by her mother to get tattooed. The more she got tattooed the more she showed off. Even if she still remembers the pain, she felt beautiful once it was done, Bouglada said. She was very proud of her stars on her cheeks. Her eldest sister had been tattooed before her and she wanted to imitate her. Bouglada said she has now given away all her silver jewellery to atone for the sin that believers told her she had committed by being tattooed. (Photo by Zohra Bensemra/Reuters)

Seen in a long camera exposure, the Caldor Fire burns on Sunday, August 29, 2021, in Eldorado National Forest, Calif. (Photo by Noah Berger/AP Photo)

A traditional high altitude bonfire burns on the occasion of the Swiss National Day on the “Stanserhorn” mountain near Stans, Switzerland, Sunday, August 1, 2021. (Photo by Urs Flueeler/Keystone via AP Photo)