The Dying Gaul is a famous Roman sculpture that dates back to the 1st or 2nd Century A.D. It's a masterful depiction of pain and sorrow by a traditional enemy of Rome by an artist whose name, sadly, is lost from the pages of history.
We do, however, know who composed The Dying Ninja Turtle. Brett Kern, a ceramics artist, made it and several other mashups of 1980s pop culture and ancient Greco-Roman statuary. You can see others at The Nerdist.