This particular square was where most of the replica statues were because they don't let you take photos of the originals in the museums. A lot of them had things like that on them that were sculpted but colored black like that. You can see the club in the hand of the statue on the far right. I'm not sure if it's there and colored like that to show what's missing on the originals or if that's how the originals look but I noticed a few like that.