I visited a website once where scrolling up or down made the sky transition from light blue and clouds to the dark blackness of outer space. I thought it was so cool I wanted to make a shirt that did the same thing.
I think this design looks best on really dark blue, but black looks pretty good, too. Depending on which kind of tee you prefer you might not have a choice.
I like this monster a lot, and I made an 8 foot tall one out of plywood and put it in my front yard behind a flower bed.