If your pet rock is anything like my pet rock, he or she's been dead for years, either from being left outside or starvation or not being able to breathe underwater, but now you can bring them back to life!!!
Now for all you over achievers start attacking your dead pet rock's face with that sandpaper, if you're worried you might hurt him, don't be he's dead, he can't feel a thing.
Now for the rest of us flip the pet rocks dead body over and simply draw a new happy alive face on there, but NEVER EVER, EVER flip the pet rock back over to the other side or else... uh... rock poltergeists will infest your home, but other than that nothing really bad will happen I mean what can they do they're rocks.
Step 3: It's Alive!
Now your pet rock is alive and happy and the two of you can spend many more happy years together, or at least a few days until you forget about him again and suffocates under the huge pile of stuff in your closet, but until then have fun!