A burning tree is seen during a fire in an area of the Amazon rainforest in Itapua do Oeste, Rondonia State, Brazil, September 11, 2019. (Photo by Bruno Kelly/Reuters)

A man takes a selfie next to a burning barricade during a protest against the government in the streets of Port-au-Prince, Haiti, February 10, 2019. (Photo by Jeanty Junior Augustin/Reuters)

An Iraqi soldier stands guard as a pipeline burns in the background after an explosion 30 kilometers (20 miles) northeast of Tikrit, Iraq, Monday, February 11, 2008. (Photo by Bassem Daham/AP Photo)

Light painting on the beach at Walton-on-the-Naze in Essex, United Kingdom on April 25, 2023 using burning steel wool spun around on a rope sending sparks flying. (Photo by Kevin Jay/Picture Exclusive)

A burned vehicle sits among a destroyed home in the Mountain fire, Wednesday, November 6, 2024, near Camarillo, Calif. (Photo by Ethan Swope/AP Photo)

An air tanker flies low over a wildfire burning on the edge of the Cariboo region city of Williams Lake, British Columbia, Canada on July 21, 2024. (Photo by Spencer Stratton/Handout via Reuters)

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.

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)