The high-voltage supervillain known as Electro started out as Max Dillon, an average but greedy electrical worker, who, in a freak accident, was transformed into a human generator, able to produce as much as 10,000 volts a minute. Calling himself Electro, Dillon used his powers for criminal activities, and was often confronted by Spider-man, making them enemies.
Electro's powers include being able to project blasts of lightning from his body, as well as create force-fields and manipulate electrical devices. He can charge himself to nearly unlimited power levels, making him one of the most powerful human villains in the Marvel universe. He is egotistical, hot-tempered, and a bit crazy. He can also be shorted-out with large amounts of water, and can be easily taken out with a punch (if you can get close enough).
Electro joined several other supervillains, led by Doctor Octopus, in a group known as the Sinister Six to attack Spider-man, as well as several versions of the group afterward. He has also been a member of the Emissaries of Evil and the Frightful Four.
Recently, Electro was hired by an unknown villain to cause a mass breakout in all of the supervillain prisons in order to free the X-men foe, Sauron.
In one comic line, Electro had a daughter, Aftershock, who was born with electric powers like his, but they were on different wavelengths, and would both be induced to intense pain if they came near each other. Eventually, with help from Spider-Man and Spider-Girl, they overcame this difficulty to be together.