I've never tried to animate anything like lightning before, so before I attempted it I knew I'd have to do quite a bit of research. Fortunately we were lucky enough to encounter two lightning storms over the course of this project and I managed to get some video footage of the lightning from a friend's bedroom window, which you can see below. I found watching real lightning myself to be extremely useful, if not for the footage (which I know isn't the clearest) then for the atmosphere, lightning, and general intensity and excitement that you can only experience when waiting in anticipation for lightning to strike. It may sound silly, but it was honestly a brilliant experience, even the scent of the air was different than normal. Obviously I can't convey a smell through my animation, but hopefully experiencing these storms first hand will allow me to make the atmosphere in my film more convincing.
Below are a few excellent super slow motion lightning videos I found online which have proved to be invaluable animating resources. In particular for the changes in the intensity of the flashes before the bolt strikes, which are usually too fast to register.
These last three videos are of plasma balls, which, while not technically lightning, have proven to be great references for how the lightning might act once actually trapped inside the bottle.