Something you could try is to do a dramatic fast-motion zoom "into" the nebula billboard, and when you get close, do a quick fade through to different footage inside a BC Fuzzball nebula with the ships emerging from the gloom. The fuzzball would have to match the color of the part of your image that you zoomed in on to make it convincing. It'd be cool with silence or building tension in the music during the zoom, and then shocker music when the borg emerge.