No, you may’t “redirect” a spell or skill that manner. Electro’s skill will fizzle as a substitute.
Focused spells and skills test the legality of their goal(s) twice: as soon as when casting/activating/triggering, and once more after they resolve. In case your opponent chooses to pay for Electro’s skill, then its focused, damage-dealing half goes on the stack and he has chosen you as its goal.
For those who give your self hexproof in response, that solely means the power will fizzle, that means that when it resolves, it should as a substitute be faraway from the stack with out impact as a result of all its targets have turn into unlawful. Your opponent cannot and doesn’t have to decide on a brand new goal.
608.2b If the spell or skill specifies targets, it checks whether or not the targets are nonetheless authorized. [..] If all its targets, for each occasion of the phrase “goal,” are actually unlawful, the spell or skill doesn’t resolve. [..]
You possibly can pressure your opponent to focus on themselves by giving your self hexproof earlier than Electro leaves the battlefield (for instance in the event you get hexproof in response to Wrath of God, earlier than it resolves), however in that case, your opponent may merely decline to pay mana when the primary a part of the power provides them the selection to pay X.
