This is John Darnielle of the Mountain Goats doing an acoustic cover of the Ace of Base song The Sign. It is absolutely glorious and having watched this I now love him three times as much as I did before, for both his ongoing personal awesomeness and for his abiding love for Ace of Base.
I also learned that the lyric is “love is demanding / without understanding” and not “love is demanding / rhythm to understanding” which means I have been singing the wrong thing all of these years. Whoops!