July 13, 2016: Katy Gets Shady on Twitter
Based on the "Regina George" tweet, the VMAs Twitter mess, and so on, it's clear Katy likes to get her feelings out on Twitter. In this case, once again, she doesn't mention Taylor by name, but it's all about context. Earlier in the day, Taylor reportedly claimed a writing credit on the new Calvin Harris song, "This Is What You Came For." This inspired Calvin to rant about Taylor on Twitter; he even mentioned Katy by name. Her Hillary Clinton GIF dropped shortly after that.