Tee Fury is a website where people submit neat art and designs which might bet featured on a T-Shirt for sale for 24 hours. There are a lot of creative designs that come through. The problem is each shirt is available for 24 hours only. So if you miss it, it's gone. And so I discovered this one a day too late. Pretty cool, regardless.
If you don't recognize the reference, it is a basic and common spell in Dungeons & Dragons. It's presented in the colors and font of 2nd Edition Advanced Dungeons & Dragons.