Maxis has released the Spore Creature Creator today, which you can either snap up now for less than a fiver or download the demo for free.
Although it's a (large) part of the upcoming game Spore, the creature creator is a stand-alone product that allows you to shape, paint and play with your own custom-created creatures that can be used in the full game.
To give you an idea of how far you can push the creature creator, we suggest you take a look at PC Gamer's own phallic contribution to the Spore universe.
For the moment, creatures created can be uploaded to the Sporepedia to show off to the world. You can also take photos, upload videos to YouTube, post images on your blog and create an avatar for your preferred social networking site.
We're expecting all manner of offensive creations to be on the web before the day is out. Add your obscene animal by downloading the program from Spore.com