Billie Eilish's "Bad Guy" is one of the biggest songs of the year.In fact, it's so popular that it was the one to dethrone Lil Nas X's "Old Town Road" after that track spent a record-breaking 19 weeks on Billboard's Hot 100 chart.. With success comes covers, and with covers come parodies. "Bad Guy" has racked up some pretty wonderful renditions in each category.