A volunteer approaches a male toad to pick him up from a road near Berlin on March 18, 2012 in Gueterfelde, Germany. (Photo by Sean Gallup/Getty Images)

A father crosses a road with his twin daughters in Shanghai, China September 28, 2018. (Photo by Aly Song/Reuters)

A car drives through a flooded road following heavy rain in Gaza City on December 27, 2019. (Photo by Mohammed Abed/AFP Photo)

A woman crosses a road outside the EU Parliament ahead of the EU elections in Brussels, Belgium, May 22, 2019. (Photo by Yves Herman/Reuters)

Workers repair a damaged road, in the aftermath of an earthquake, near Anamizu, Japan on January 3, 202. (Photo by Kim Kyung-Hoon/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 girl gets a helping hand across the road in Swansea, Wales, England on December 31, 2017. (Photo by Athena Picture Agency)

Traffic police stand at the side of a road in Pyongyang on November 25, 2016. (Photo by Ed Jones/AFP Photo)