Slick's theme! The main melody, a sad, grim rendition of Littleroot, is the same as last time, but the strings follow a tune that is also present in the themes for each of his Pokemon. (At least, it should be. I might've accidentally removed it from Ferricia's...) And I tried to fit in bits of the Hoenn E4 theme, as he is one of them, after all.
2012 version for comparison.
I accidentally overwrote the 2016 version so it's gone