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 striking funeral worker takes a break near a casket placed at a parking lot as they protest over changes to a host of procedures and regulations, during the coronavirus disease (COVID-19) outbreak outside the department of home affairs in Soweto, South Africa, September 16, 2020. (Photo by Siphiwe Sibeko/Reuters)

A person wearing a face mask is reflected in an art work entitled “A=V” by Ben Cullen Williams, amid the coronavirus disease (COVID-19) outbreak, in Covent Garden, London, Britain on October 16, 2020. (Photo by John Sibley/Reuters)

Masks based on real people's faces are diplayed at the Shuhei Okawara's mask shop in Tokyo, Japan on December 16, 2020. (Photo by Issei Kato/Reuters)

Ground personnel tend to actress Yulia Peresild after the landing of the Soyuz MS-18 reentry capsule with herself and director Klim Shipenko of the “Vyzov” (The Challenge) film crew as well as Roscosmos cosmonaut Oleg Novitsky on board, in steppes southeast of Jezkazgan, Kazakhstan on October 17, 2021. (Photo by Sergei Savostyanov/TASS)

A seller dressed as Snegurochka (The Snow Maiden) shows Christmas toys at the Christmas decorations set in the Moscow GUM State Department store in Moscow, Russia in Moscow, Russia, Monday, December 16, 2019. (Photo by Pavel Golovkin/AP Photo)

A woman is arrested during a mass gathering protest organised by the group called “UK Freedom Movement”, in Hyde Park in London as the country is in lockdown to help stop the spread of coronavirus, Saturday, May 16, 2020. The group claims that the coronavirus lockdown is illegal. (Photo by Kirsty Wigglesworth/AP Photo)