User blog comment:Lightning the Skrill/Skrill's Lightning Blast; White Fire?/@comment-24413325-20150326130009

Mybe they replaced the skrill's fire with lightning in Defenders of Berk, to look more 'cool'. (I mean, they changed Thornado's body(his legs) too, just to make him able to walk), I think the Skrill in Book of Dragons is the original, and the DOB one is a newer version