It wasn't Nikola Tesla who electrocuted an elephant, it was Thomas Edison. He wanted to discredit Tesla's AC system by showing it was more dangerous than his DC system as well as to promote his system. Apparently he instructed his technitians to kill quite a few animals with AC systems.

Thomas Edison isn't a great inventor. He was a cruel, plagrising **** who stole Nikola Tesla's fame.

This competition was called the 'War of Currents'.