he is governed by the reptilians 

 From Reddit:

This particular chasuble was made as a gift to be worn by the Pope during his trip to Peru. As such the maker decided to put something that is "Peruvian" with that thing being an image from the Nazca line. And that basically is the reason. A kitsch artistic motif to be sure but it's neutral and the image has no implied ulterior meaning anyway to modern onlookers. I dont like it but purely for aesthetical reasons.