I would say it's a toss up between Bad Sweets, Bad Dream (バッド•スイーツ、バッド•ドリーム) and either this song or really any song by DJ Mass Mad Izm. Pretty much ANY song involving him will have crazy scratch spam lol. Bad Sweets Bad Dream is NOT one of his songs but it is pretty beastly with the scratches plus there are a lot of charge scratches thrown in there for good measure. Even Dolce at some point was having a hard time navigating those scratches but he finally full combo'd it a couple months ago during one of his live streams.