I found the image via google. Some kid had tons and tons of fantasy clip art and stuff.
This poster is sub-titled 'unicorns are extinct because they couldn't handle their coke'
Originally, I was planning on using the 'My Little Pony' unicorn but because I had already ripped off GI Joe for the Noise Pop series I went for something else. Ripping off Jason Munn is fun -- it wasn't my intention but when I was about half-way done I realized I realized the illustration style is very similar to the stuff he uses.