Durning a lightning storm a grey jellyfish looking craft that emitts no light changes in to a 3-D rectangle with lights.

A severe thunderstorm came through and about 30 minutes after the thunder and lightning had begun, my husband and I were watching the lightning storm.  The lightning was striking fast and the entire sky was lighting up.  My husband then asks me what is floating in the sky.  I look up to where was pointing and I see it.  It was a grey craft that looked somewhat like a jellyfish with no lights emitting from it. It moved in what I can only describe as an organic manner.  We watched for a few minutes as it moved from one place to another.  Some times we lost track of where it was but would see it again only a moment later, as it stayed in the same general area.  Then it ended up flying closer to us and when the sky lit up again the grey craft tuned in to what looked like a geometric 3-d rectangle.  The outer edges of the “rectangle” were lit up with all different colors.  After the lightning strike and the sky went dark the craft again looked like the grey jellyfish with no emitting light.  It then moved back to its previous general location but looked a little paler than it had at first.  Maybe it was further away and we could not see it as well.  After about 30 minutes we were no longer able to see it.