Also, here is one example. If you follow the picture link you can read the “The Pope is the antichrist” meme associated here.

http://blessedquietness.com/crosinvt.jpg LINK (WARNING: Very anti-Catholic)

I would just laugh at anyone who says this and their lack of knowledge of apostolic history.

The Gospel of John lets us know that Peter would be crucified and the dramatic change in his humility from his initial time with Christ to the time of his leters shows us that it is quite possible ( I would say likely) that he would request upside down crucifixion.

The usurping of the inverted crucifix (which was distorted when protestants removed the corpus into an inverted cross) by anti-christians i can only assume was begun at a very early date to insult and generally vex Christians. Anything further I dont know.