Katy Perry is a pop artist whose hight of career conflicted with Taylors. The song Bad Blood was written from the conflict and drama that was created back in the 1989 era. (as well as Katy's song Swish Swish was written allegedly about Taylor) After not being on good terms, Taylor and Katy solidified and publicized their good terms in the You Need To Calm Down music video, where Taylor was dressed as french fries and Katy was dressed as a burger.