Smoke is fun to play with. The 2nd one to me looks like some kind of "being" with a head and arms that come out of a body. I noticed where you merged the photo together to get the effect though. Blend them together a little better and it'll look real good
Same here. I've been doing similar experiments with water, but smoke is so organic and lovely. I hope you don't mind I had to try playing with this, so I created an alternate edit from your first image. I just took one quarter and mirrored it over itself, set to "lighten only" mode. I think it looks like some sort of animal skeleton.