Nikola Tesla invented many brilliant devices such as electric oscillators and the Tesla coil. He was also quite gifted at inventing ways to get out of debt. One of those methods led him to pay off a hotel bill with a “death beam.”

Despite Tesla’s creative genius, he suffered from insufficient income in his later years. After running up a $20,000 bill at the Waldorf-Astoria, he was forced to sell his Wardenclyffe tower plant, where he experimented with wireless transmission of data.

Within twenty years, he had again run up a huge hotel bill; this time at the Governor Clinton Hotel in Manhattan. When the hotel’s management demanded payment, Tesla offered them something better than money: the rights to one of his most astonishing inventions to date.

He referred to his invention as a “Death Beam.” He said it was so deadly that it could explode if anyone tried to open its box without taking proper precautions. He said he had already built a working model of the device and would be making a public demonstration in a matter of months.

The hotel management knew a good deal when they saw one, and they willingly accepted the rights to the invention as payment in full for Tesla’s lodging. Tesla gave them a wooden box, containing the prototype, but cautioned them about the dangers of opening it.

The brilliant inventor was struck by a car later that year, and he never fully recovered from his injuries. Five years later he died at the New Yorker Hotel — where he also ran up large, unpaid debts.

Upon Tesla’s death, the owners of the Governor Clinton Hotel engaged top scientific experts to carefully open the box so they could finally get a look at the mysterious and deadly Death Beam. John G. Trump (uncle of President Donald Trump, was the MIT scientist tasked with opening the box and examining the device. He wrote that he paused and reflected on his life before mustering the courage to unseal the box. What he found was a bunch of comparatively-worthless electrical components. Military experts searched Tesla’s possessions, looking for any clue as to his wonder weapon, but came up with nothing.

Many rumors persist that Tesla did, indeed, create a Death Beam, and its secrets are safely locked away in the most secure files of the Pentagon. Others point to Tesla’s increasing mental disturbances in his later years and conclude the Death Beam was just a big con to get him out of a huge bill. Whatever the truth about Tesla’s mysterious Death Beam, we can conclusively say that it was successful in killing off some very inconvenient debt.

Read more fun facts about Nikola Tesla.

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Read about the time Albert Einstein offered his wife his Nobel Prize money as a divorce settlement.