A family poses for photos near a dinosaur exhibits along the Changi Jurassic Mile as it is light up for Christmas near Changi airport in Singapore on December 8, 2020. (Photo by Tim Chong/Reuters)

Migrant children play with leaves during Christmas Eve at a shelter, as they travel with their parents as part of a caravan with humanitarian visas to transit throughout the country, in Monterrey, Mexico on December 24, 2021. (Photo by Daniel Becerril/Reuters)

Tens of millions of red crabs make their way across Christmas Island, Australia on November 13, 2021 during their annual migration from the forest to the ocean, swamping roads and bridges. (Photo by Parks Australia/Animal News Agency)

A girl looks on at a diver dressed as Santa Claus performing during a promotional event for Christmas in Seoul, South Korea on December 3, 2021. (Photo by Kim Hong-Ji/Reuters)

Divers perform during a Christmas-themed underwater show at the Aqua Planet 63 aquarium in Seoul on December 8, 2022. (Photo by Anthony Wallace/AFP Photo)

Santa Claus rides in his sleigh as he prepares for Christmas in the Arctic Circle near Rovaniemi, Finland December 15, 2016. At Santa Claus' Lapland home in Finland, his helpers sort out piles of letters from around the world, each detailing children's requests for this Christmas. (Photo by Pawel Kopczynski/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.

A Christmas Tree goes up in flames in a controlled-setting demonstration by the Glendale Fire Department on December 13, 2023, in Glendale, California. Firefighters showed how quickly a dried-out tree can ignite. According to the National Fire Protection Administration, Christmas trees account for hundreds of fires each year, often ignited by shorts in electrical lights or open flames from candles, lighters or matches. (Photo by Frederic J. Brown/AFP Photo)