I thought the same thing. Taylor Swift? Former emo band gods Panic! At The Disco? BRENDON URIE?! How could you!
Just kidding, it's not that dramatic. It's not the first time Brendon did a somewhat unexpected collaboration. Remember his collaboration with Every Time I Die, with their song "It Remembers" back in 2016? ETID is a pretty heavy band. He's also done collaborations with Travie McCoy, Lil Dicky, and benny blanco & Juice WRLD, so it's not completely out-of-the-ordinary for him to explore other genres.
Check out the video. I actually really like it! It's very fairy tale/fantasy-esque. The song however. might take a few more listens for me to be a fan. What do you think?