Thunder notices the sudden increase of technological use in Equestria, so he decides to create some sort of pendant that could generate clean, low-cost energy.

Instead, his plan backfires.

The pendant ends up blocking electricity to be generated into any electrical device. In english, it turns electricity off.

He first finds this as a failure. But it quickly becomes something for fun.

But what happens when this "fun" ends up getting into the wrong hooves? Can Thunder fix it all before Equestria ends up in eternal darkness?

Based off of the pendant in NBC's "Revolution", that does the opposite of what it does in this story.