This somewhat famous rock was painted by artist Ray Bubba Sorenson. For generations, kids have painted slogans, names, and obscenities on this rock, changing it's character many times. Now, it stays painted with something worth seeing. Each year around Memorial Day, Ray uses white paint to cover over his previous year's work, then spends one to three weeks creating new scenes on his blank canvas.
A visitor's information board has been added recently, too, with information about the rock and photos of it from previous years. Be sure to check out the rock and the information while you're here, and leave a note for Bubba in the notebook on the information board!
More information is available at the artist's home page and Snopes.com

Placed by a happy Nebraskacher