Thomas Edison was a cut-throat capitalist that would do anything to get ahead in the AC vs DC wars including electrocution of animals.
The 'War of the Currents' was a publicity spat between Edison, who was promoting his direct current (DC) electricity supply and Westinghouse who used Tesla's alternating current (AC). The DC system was safe but could only be used in a very small area as it couldn't be carried over long distances. AC could be distributed much more easily but required a high voltage which would be dangerous if anything living came into contact with it.
In an attempt to discredit Westinghouse, Edison presided over a number of public electrocutions of stray cats and dogs until in 1903 Topsy, a circus elephant who had killed three people, was ordered to be put down and Edison offered to electrocute her. The execution on Coney Island was witnessed by 1,500 people. 460 grams of potassium cyanide was hidden in carrots and fed to her. Wooden sandals lined with copper were then attached to her feet and a current of 6,600 volts was sent through her body. She died 'without a trumpet or a groan'.
Edison filmed the event and tried to persuade people to refer to electrocution as being ‘Westinghoused’ but eventually AC became the accepted norm when Westinghouse and Tesla were commissioned to build the Niagara Falls AC hydroelectric plant in 1893.