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.

“The Eton wall game is a game similar to football and Rugby Union, that originated from and is still played at Eton College. It is played on a strip of ground 5 metres wide and 110 metres long next to a slightly curved brick wall, erected in 1717”. – Wikipedia

Photo: The “Collegers” and the “Oppidans” of Eton College take part in the “Wall Game” as boys in their traditional school uniform watch from on top of the wall on November 17, 2007 in Eton, near Windsor, Berkshire, England. The first recorded “Wall Game” took place in 1766 with competition between the two houses at the boarding school remaining as fierce as ever on the annual St. Andrew's day event. The object of the game is to get the ball to either end of the wall and score a goal, which has not happened since 1909. As well as scoring a goal the players can win points with a “shy”, where the ball is held against the wall and touched by the hand and awarded one point. (Photo by Christopher Furlong/Getty Images)

Frost covers part of the face of University of Minnesota student Daniel Dylla during a morning jog along Mississippi River Parkway Tuesday, January 29, 2019, in Minneapolis. Extreme cold and record-breaking temperatures are crawling into parts of the Midwest after a powerful snowstorm pounded the region, and forecasters warn that the frigid weather could be life-threatening. (Photo by David Joles/Star Tribune via AP Photo)

Madson of Santos reacts during the match between Santos and Palmeiras as part of Brasileirao Series A 2022 at Vila Belmiro Stadium on May 29, 2022 in Santos, Brazil. (Photo by Carla Carniel/Reuters)

Los Angeles Kings center Zack MacEwen, left puts Edmonton Oilers center Ryan McLeod int the bards during the second period in Game 3 of an NHL hockey Stanley Cup first-round playoff series Friday, April 21, 2023, in Los Angeles. (Photo by Mark J. Terrill/AP Photo)

Denmark's Katrine Veje, left, is comforted by Australia's Charlotte Grant, right, after the Women's World Cup round of 16 soccer match between Australia and Denmark at Stadium Australia in Sydney, Australia, Monday, August 7, 2023. (Photo by Rick Rycroft/AP Photo)

A BYU fan show his support during the first half of an NCAA college football game against Oklahoma, Saturday, November 18, 2023, in Provo, Utah. (Photo by Rick Bowmer/AP Photo)

Emma Raducanu of Great Britain receives treatment in her women's singles first round match against Bianca Andreescu of Canada during day three of Internazionali BNL D'Italia at Foro Italico on May 10, 2022 in Rome, Italy. (Photo by Alex Pantling/Getty Images)