Actually on second viewing what I thought was a sign of projector trail, doesn't look bright enough, it looks almost like a clouds.

Not sure, it's hard to tell how big it was. I think its possible it was some people just shining something from over the hill, but maybe it is something burning up in a pretty way.

Maybe an impressive firework? Depends how long it lasted and how big it was, impossible to tell from the footage.

Cool vid though.