Around the turn of the last century, Edison researched and developed electricity, specifically direct current (DC) electricity. There are two types of electricity that we use today: direct current and alternating current (AC). In the U.S., AC is the standard, but that wasn't always the case.
Back in the early 1900s, the AC/DC debate was similar to the VHS or Beta videotape wars of the 1980s. Which type would win out? Scientists got pretty competitive. Edison was making big money off of his DC patents, since it was the standard in the U.S. at the time, so when George Westinghouse and Nikola Tesla discovered a competing form of electricity -- that happened to be more efficient and less expensive -- things got ugly [sources: Long,PBS].
In an effort to discredit Westinghouse's and Tesla's AC electricity, Edison did what any level-headed scientist would do: He electrocuted a bunch of animals to show that AC current was more dangerous than DC. He even called these electrocutions "getting Westinghoused" [source: Long]. He started these "experiments" on smaller animals, like dogs and cats, but when the Luna Park Zoo on Coney Island had an elephant named Topsy that they were planning to put down, Edison jumped at the chance to electrocute her [source: Long].
All of those cruel animal deaths turned out to be for naught. Because of some complications with DC, the U.S. ended up adopting AC as the electrical standard despite Edison's wrong-headed efforts [source: Long].