The Cotopaxi volcano, one of the world's highest active volcanoes, spews smoke as seen from El Pedregal, Ecuador, October 22, 2015. Ecuadorian authorities are monitoring activity at Cotopaxi volcano, which prompted Ecuador's President Rafael Correa to maintain a yellow alert for eruptions as bursts of ash keep spewing from the snow-encircled crater of the volcano and falling in gusts on residential communities. (Photo by Guillermo Granja/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 Tengger tribesman prays at Mount Bromo during the annual Kasada ceremony in East Java on August 12, 2014. The Kasada ceremony is a festival held every 14th day of the Kasada month in the traditional Hindu lunar calender to honour Sang Hyang Widhi (God Almighty) and is based on the legend of Roro Anteng and Joko Seger from the Majapahit Kingdom, from which their Tengger tribe name originates. Hundreds of worshippers from the Tengger tribe offer food and livestock as a symbolic sacrifice which they throw into the crater for the blessings of safety and prosperity to their familyies and community. (Photo by Juni Kriswanto/AFP Photo)

Mount Etna erupts near Sicily, Italy on March 15, 2021. This is the thirteenth time in twenty-eight days. During the early evening of 14 March and the night between 14 and 15 March a strombolian activity at the Southeast Crater gradually increased, leading to a paroxysmal event which had its peak around 01:00 am, ash blown by the wind touched the south-southeast slope of the volcano reaching also Catania, the event ceased completely around 3:45, photo taken from Milo near Catania on March 15, 2021. (Photo by Salvatore Allegra/Anadolu Agency via Getty Images)

Journalists report during a media tour near the volcano on the island of La Palma in the Canaries, Spain, Wednesday, September 22, 2021. A volcano on a small Spanish island in the Atlantic Ocean erupted on Sunday, forcing the evacuation of thousands of people. Experts say the volcanic eruption and its aftermath on a Spanish island could last for up to 84 days. The Canary Island Volcanology Institute said Wednesday it based its calculation on the length of previous eruptions on the archipelago. (Photo by Emilio Morenatti/AP Photo)

This handout photograph taken and released by the Center for Volcanology and Geological Hazard Mitigation on April 17, 2024, shows Mount Ruang spewing hot lava and smoke as seen from Sitaro, North Sulawesi. A volcano erupted several times in Indonesia's outermost region overnight on April 17, forcing hundreds of people to be evacuated after it spewed lava and a column of smoke more than a mile into the sky. (Photo by Handout/Center for Volcanology and Geological Hazard Mitigation via AFP Photo)

A violent eruption spews ash more than a kilometer into the sky above Mount Etna in Sicily on February 23, 2021. (Photo by Marco Restivo/Barcroft Studios via Getty Images)