What We Do in the Shadows premiered on FX in 2019, adapting the 2014 mockumentary film by Jemaine Clement and Taika Waititi into a Staten Island vampire sitcom. Matt Berry's Laszlo quickly became the show's breakout voice, with his clipped insults and grand pronouncements clipped endlessly for reaction videos. The devious bastard line fits that pattern perfectly, surviving because it works without any setup and instantly signals sneaky behaviour. Fans keep reusing it for pranks, betrayals and petty drama online.