Members of a comparsa, a Uruguayan carnival group, dance during the Llamadas parade, a street fiesta with traditional Afro-Uruguayan roots in Montevideo February 9, 2017. (Photo by Andres Stapff/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 gaucho is unseated by an untamed horse during the Creole week celebrations in Montevideo, Uruguay on March 26, 2018. (Photo by Andres Stapff/Reuters)

A gaucho rides an unbroken or untamed horse during Creole week celebrations in Montevideo, March 23, 2016. All Easter week gauchos all over Uruguay and neighboring Argentina and Brazil come to Montevideo to compete for the award of best rider. (Photo by Andres Stapff/Reuters)

A man dressed in a condom costume walks at Caleta Portales beach, during a summer awareness campaign by the Chilean Corporation for the Prevention of AIDS in Valparaiso city, northwest of Santiago January 9, 2015. (Photo by Rodrigo Garrido/Reuters)

Participants with the word “Harta” on their bodies, link arms as they mark International Women's Day at Avenida 18 de Julio in downtown Montevideo, Uruguay March 8, 2021. The word is a term to say exhausted or “had enough” but used by women. (Photo by Mariana Greif/Reuters)

A gaucho is unseat by a wild horse during the annual celebration of Criolla Week in Montevideo, March 30, 2015. Throughout Easter Week, “gauchos”, the Latin American equivalent of the North American cowboy, from all over Uruguay and neighboring Argentina and Brazil will visit Montevideo to participate in the Criolla Week to win the best rider award. The competition is held from March 29 to April 5 this year. (Photo by Andres Stapff/Reuters)

People observe a 1947 Mercury during the 25th edition of the "1000 millas sport e historicos" (1000 miles sports and classic) race in Montevideo, October 28, 2015. The race will cover 1000 miles from 28 to 31 of October. (Photo by Andres Stapff/Reuters)