Now I don't normally post in these topics.
But what on earth is the point of spoiler tagging a youtube link.
The people who want to listen it will click the link, those who don't want to listen to it won't. Plus the song itself isn't a spoiler at all, it contains some background information but nothing major or important, and the only reason I can think that people would have not to listen is if they want to save it for being in the episode itself. Do watch out for the comments though.
Also, the song is awesome.
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^Poorly disguised anti-caps sig