Electro, Assaulting Battery is a rare Legendary Creature — Human Villain card from Through the Omenpaths (OM1), collector number 76.
Flying You don't lose unspent red mana as steps and phases end. Whenever you cast an instant or sorcery spell, add {R}. When Electro leaves the battlefield, you may pay {X}. When you do, he deals X damage to target player.