Not much was "done by hand" in this case. I used 3 very "disturbed" stars with various settings (Unioned together) to create the basic shape. The highlights and shadows are merely a matter of making offset copies of my base shape, doing a difference of an offset and the original for each effect, blurring the results, then grouping and clipping the two lighting effects. This allows me to change the base color to resemble ink or paint or even glowing toxic waste.
Also, I've made some improvements to the results of my technique. The new splat is much smoother looking than my initial posting! More liquidy-looking gooeyness!!!
I'll definitely put a tutorial together over the next few days.