The character is a Spider-Man nemesis who acquires the ability to control electricity after he's struck by lightning. The character first appeared in The Amazing Spider-Man #9 back in 1964.
Lightning figures prominently in a post-credit sequence scene in The Amazing Spider-Man, hinting at the likelihood that Electro may appear in the sequel.
Along with Andrew Garfield, Emma Stone is set to reprise her role, while Shailene Woodley is in talks to play Spidey love interest Marty Jane Watson.
The Amazing Spider-Man took in over $262 million domestically and over $750 million worldwide this year.
[Source: Variety]