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.

Aymara witchdoctor Ricardo Quispe, also called “Lord of the Lake”, throws coca leaves during a ritual to predict the future, at the witches market of El Alto, on the outskirts of La Paz, December 31, 2014. Dozens of witch doctors tend to a warren of stalls in El Alto, making offerings to give thanks, to promise luck at work or in love, or to call up spirits and banish curses at the end of the year. (Photo by David Mercado/Reuters)

The Fighting Cholitas are a group of female wrestlers who perform in El Alto, Bolivia. Tickets to the exhibitions cost $1. Like the general population of El Alto, which consists almost entirely of Aymara and Quechua residents, the Cholitas are indigenous. They wear braided hair, bowler hats and multilayered skirts in the ring. Here: Barbara Quisbert and Susana La Bonita, cholitas wrestlers, fight during their return to the ring after the coronavirus disease (COVID-19) restrictions, in El Alto outskirts of La Paz, November 29, 2020. (Photo by David Mercado/Reuters)

Egyptian 26-year-old dancer Nadine El Gharib, dances on the rooftop of her home in Cairo, Egypt, Monday, September 27, 2021. “Dance was crucial when COVID-19 started in terms of taking care of my well-being”, Gharib said. “When restrictions forced us to stop going to the Opera for classes I started online dance and it introduced me to a new world of dance. It was very inspiring”. (Photo by Nariman El-Mofty/AP Photo)

Catholic faithfuls hold figurines of baby Jesus during a religious procession on Holy Innocents Day in Antiguo Cuscatlan, El Salvador, December 28, 2016. (Photo by Jose Cabezas/Reuters)

Girls watch a procession during the “Fiesta de las Palancas” celebration to ask for blessings and abundance during the new year in Panchimalco, El Salvador, January 5, 2017. (Photo by Jose Cabezas/Reuters)

Mohamed Gamal Abdel Nasser, a workshop owner, tests primus stoves known as “Bagour” in Arabic, in Cairo, Egypt, May 11, 2016. (Photo by Mohamed Abd El Ghany/Reuters)

Students walk to school on the first day of their new school year in Giza, south of Cairo, Egypt September 25, 2016. (Photo by Mohamed Abd El Ghany/Reuters)