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.

Steamed Chinese-style buns, known locally as salapao, are decorated with faces during the start of the annual 10-day vegetarian festival in Bang Saphan, southern Thailand on October 13, 2015. (Photo by Matthew Richards/Courtesy Image)

A pitch invader during the 2018 FIFA World Cup Final between France and Croatia at Luzhniki Stadium on July 15, 2018 in Moscow, Russia. p*ssy Riot claimed responsibility for the pitch invasion, tweeting: “Just a few minutes ago four p*ssy Riot members performed in the FIFA World Cup final match – «Policeman enters the Game»”. (Photo by Darren Staples/Reuters)

Switzerland's Belinda Bencic celebrates after defeating Czech Republic's Marketa Vondrousova during their Tokyo 2020 Olympic Games women's singles tennis final match at the Ariake Tennis Park in Tokyo on July 31, 2021. (Photo by Yara Nardi/Reuters)

Detroit Lions cheerleaders perform a routine with the Grinch during a timeout in the action in the second quarter of the Detroit Lions against the Green Bay Packers at Ford Field in Detroit, Michigan on December 5, 2024. (Photo by Lon Horwedel/USA Today Sports)

A mouse rides on the back of a frog in floodwaters in the northern Indian city Lucknow June 30, 2006. (Photo by Pawan Kumar/Reuters)

People carry their pets before the start of a pet blessing at Greenhills shopping mall in Manila October 3, 2015. Pets were blessed on Saturday in a celebration honouring the patron saint of animals Saint Francis of Assisi. (Photo by Romeo Ranoco/Reuters)

Morocco's Romain Saiss, right, reacts after teammate Abdelhamid Sabiri, not visible, scored a goal on Belgium's goalkeeper Thibaut Courtois, left, during the World Cup group F soccer match between Belgium and Morocco, at the Al Thumama Stadium in Doha, Qatar, Sunday, November 27, 2022. (Photo by Frank Augstein/AP Photo)