Former Canadian Prime Minister Justin Trudeau appears to have an entirely new reason to get into the Halloween spirit: Katy Perry! "Ready for Halloween with Hadrien: he's the surfer, I'm the shark (to his left). We built the costume together - a little father-son Halloween teamwork. 🎃🦈🏄♂️," Trudeau, 53, wrote via Instagram on Friday, October 31, sharing a photo of his youngest son Hadrian Trudeau dressed as a bloody surfer, while the politician appears to dress up as the infamous Super Bowl 49 left shark.