Hey, ladies - so glad this went over well. It's for a Halloween costume ("Miss Una-verse" ha ha) but I could consider wearing it regularly too. DH actually loved it which surpirsed me - he's usually pretty "whatever" about my crafty moments.
The DIY was super-easy. I used to be really crafty but time is not on my side these days. Here's the basics (you can find plenty of tutorials online too):
HINT: Use fresh bleach (mine was 10 years old... Had to buy a new bottle.)
Put bleach in a spray bottle which has an adjustable nozzle for different spray effects. I did not dilute it, though some sites say to do so.
Per Parsley, wear glasses and gloves in well ventilated area.
Spray bleach randomly on a black cotton item (I didn't put a piece of carboard inside because I wanted to do front and back, but if you just want to do the front, you can put cardboard or a trashbag inside. You can also tape off an area to get a shape, like a triangle).
To get the swirl effect (with bonus unintended skull), I just did the old tie-dye method of twisting the fabric in a circle and sprayed more bleach in the center, let it sit, then untwisted it.
Like magic, you'll see things turn brown then red then orange - this took no more than 10 minutes.
Rinse out with son's dirty socks in laundry and dry in dryer.
I used a sponge brush and cheap acrylic paints for the "special effects" - some with glitter, some just flourescent. Planets, clouds, a shooting comet - you really can't make a mistake. The colors tone down in the fabric and can be mixed up. For the stars, I dabbed with a toothpick. Some sites suggest using a toothbrush to splatter the paint by running your finger over the bristles after dipping in white paint, but I was afraid I'd get myself in the face instead.
I'd be happy to make one for anyone who wants to send me a black item they are willing to sacrifice! It is fun, and minus the washer/dryer time only took about 1/2 hour.