An artwork entitled “Are you still mad at me?” by John Isaacs is displayed at the Death: A Self-portrait exhibition at the Wellcome Collection on November 14, 2012 in London, England. The exhibition showcases 300 works from a unique collection by Richard Harris, a former antique print dealer from Chicago, devoted to the iconography of death. The display highlights art works, historical artifacts, anatomical illustrations and ephemera from around the world and opens on November 15, 2012 until February 24, 2013. (Photo by Peter Macdiarmid)

Competitors take part in the annual Mud Madness event at Foymore Lodge on April 22, 2018 in Portadown, Northern Ireland. The adult version of the event includes two laps of an 8km course through 25 obstacles while the kids event is run over 2kms. The race is in it's eleventh year and is sponsored by McVities Jaffa Cakes and event charity partner Marie Curie together with other numerous charities and fundraising groups. (Photo by Charles McQuillan/Getty Images)

“If a man insisted always on being serious, and never allowed himself a bit of fun and relaxation, he would go mad or become unstable without knowing it”. – Herodotus. “You can discover more about a person in an hour of play than in a year of conversation”. – Plato. Photo: Mandalay, Burma. (Photo by Steve McCurry)

A member of a rival team walks during an annual carnival battle with oranges in the northern Italian town of Ivrea February 15, 2015. Dressed up as Middle Age kings' guards, a group of men ride in a horse-drawn carriage and pelt “foot soldiers” with oranges as thousands of people gather to re-enact a Middle Age battle when the townsfolk of Ivrea overthrew an evil king. In a strange twist, instead of swords and cross bows, these days the weapons of choice are oranges. (Photo by Max Rossi/Reuters)

An Alitalia plane approaches to land as starlings fly at Fiumicino international airport in Rome October 14, 2013. Italy will have to notify a planned government-led 500-million-euro bailout of near-bankrupt airline Alitalia to EU regulators who will then assess whether the measure complies with EU state aid rules, the European Commission said on Monday. (Photo by Max Rossi /Reuters)

A traveller washes his horse in the River Eden in preparation for selling at the Appleby Horse Fair on June 3, 2011 in Appleby, England. Appleby Horse Fair has existed under the protection of a charter granted by James II since 1685. It is one of the key gathering points for the Romany, gypsy and traveling community. Appleby Horse Fair is attended by about 5,000 travelers who come to buy and sell horses. The animals are washed and groomed before being ridden at high speed along the “mad mile” for the viewing of potential buyers. (Photo by Christopher Furlong/Getty Images)

In this Monday, June 15, 2015 photo, Ahmad Abu Jereda, 16, carries Max, the male lion cub, as he passes by Palestinians at the main garden in Gaza City, in the northern Gaza Strip. A pair of lion cubs are stuck at a Gaza-Israel border crossing en route to a Jordan animal sanctuary, after being kept for a year by a family in crowded Gaza. Saduldin al-Jamal had bought the cubs from the Gaza zoo, hit during last summer's Israel-Hamas war. His family would take them to parks or the beach and children – those brave enough – would come up to pet them. (Photo by Adel Hana/AP Photo)

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.