ShinjiPG posted a link to a video with Sanmon Gossip.
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Some are saying it might be a mash up sort of thing like from Ringo no Uta single :\ but I don't think it is.
I was kind of floored by the song at first. I was like "wtf is this noise?" but I think that's a sign of classic Shiina and the song is kind of growing on me.