Electricity, it was indeed a new power, unlike Ted's abilities last season.
I know nothing, spoiler-wise about Peter, so I only have speculation: Someone used him. Mind control, hypnosis, illusions, or something, somehow, he was discovered by a evolved human, and that person used him for his or her benefit. Odds are, because of the necklace, it's one of the eight or nine people that Kaito Nakamura mentioned (Hiro's Dad). Of course, it wouldn't be Peter's mother, either, and I don't think it'll end up being volume 2's major villain, or else he wouldn't have been "let go." That's my guess.