Xar kept spamming the Numa Numa link, I'm guessing he did a google search for Numa Numa videos. Everyone seems to love Hitler, I guess, since he pops up random places.
[EDIT]: After watching it, I've decided that it's not Hitler just for the Numa Numa video. That artist just took random animated gifs (the Hitler one being an old one, along with the Ninja Turtle and dancing super heros) and put them to the Numa Numa song. Here's a better compilation of gifs:
http://www.albinoblacksheep.com/flash/elvis.phpAlso, it's not Hitler breakdancing. That is
not breaking. Here's an example of a real breaking gif:
