9. Jeff Koons, Rogers V. Koons
Koons has been sued a number of times; on this occasion, the artist was sued after he appropriated a photograph taken by Art Rogers of two people holding a bunch of puppies. Although Koons made a sculpture from the photo, changing the colours of the puppies (to bright blue) and altering a few other elements, the court rejected his parody defence, and it remains one of the most noteworthy cases involving modern art today.