The first time you meet Doctor Who, says his new companion Bill (played by series newcomer Pearl Mackie) in this new trailer for the BBC America series return, you think he’s funny. Second time, amazing. And the third time? “He’s the most dangerous man in the universe.” If that doesn’t hook Who fans, the ghostly smoke-monsterish faces in this new promo for the April 15 season 10 premiere of Doctor Who should do the trick.