It's a battle of electricity manipulators with one of Academy City's Level 5 espers and one of Spider-Man's major foes:
Battle can be won via incapacitation or death. Both characters will be more serious than usual in dishing out their powers, yet are still in character.
Battle takes place in an empty San Francisco with both foes 10 yards apart from one another.
Who do you think wins this?
EDIT: And for those that ask, this battle involves Mikoto as a Level 5 esper, not while she is undergoing the Level 6 Shift she is presently undergoing in the Railgun manga.