People walk under Australia's iconic landmark Harbour Bridge in Sydney on April 3, 2019, as heavy fog blankets the city. Low visibility due to heavy fog affected traffic in the city and caused flight delays at the Sydney airport. (Photo by Saeed Khan/AFP Photo)

Racegoers shield themselves from the rain and wind at the Fairyhouse Easter Festival in Fairyhouse, Co. Meath, Ireland on April 10, 2023. (Photo by Morgan Treacy/Inpho)

Revellers brave the rain as they make the most of New Year's Eve in Liverpool city centre, UK on December 31, 2024. (Photo by Ioannis Alexopoulos/London News Pictures)

Russian riot policemen beat young PREGNANT female anti-Putin activist during a protest rally against the Presidential inauguration of Vladimir Putin on May 6, 2012 in Moscow, Russia.

Mates Jimi Hunt and Dan Drupstee dug the 650m slippery slide on a property at Helensville, northwest of Auckland and opened it this weekend as part of a festival to help combat depression.

An activist lays on the floor of a skate park during a protest against environmental destructions in Jakarta, Indonesia, 19 March 2021. Dozens of youths participated in a rally as part of the global climate strike movement demanding government to declare the climate emergency. (Photo by Mast Irham/EPA/EFE)

Members of the media document a damaged train carriage extracted from a tunnel after the deadly train derailment north of Hualien, Taiwan on April 6, 2021. (Photo by Ann Wang/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.