Liquid Flame

So I was messing around with Photoshop the other day and an old sketch, and by fluke I ended up with this. Well not so much a sketch but a nearly finished pic; it's a bit to clean to be a sketch. But I digress, the neat thing I managed (by mistake I might add) is the flame. First I scanned the pic and darkened the lines because they were barely visible. Then on a new layer I used the ploygon lasso tool to make a random shape. Then I filled it with a rainbow gradient. I copied the layer painted in some random stars in various colours, and put a glowing edge filter on it. Now here's where my fluke happened. I accidentally hit the liquid button on the filter menu. I experimented and ended up with what you see. I duplicated the effect on both layers of the flame and there you have it. I left the rest as is to make the flame stand out.