Aliens who come to Earth inevitably get hooked on our human vices. It's just a natural law of the cosmos. And sooner or later, every extraterrestrial wants to smoke. It's a filthy habit, but just barbaric enough to seem fascinating.

We've made a special video tribute to aliens who like to smoke, with clips from Star Wars, Star Trek, Doctor Who and X-Files, among many others.

Music: "Smoke with a Hippie" by Wildebeast, via Free Music Archive.

Additional reporting by Mandy Curtis and Katharine Trendacosta. Thanks also to Kim Beavers, John Bowker, Henry Baum, Stephen Kane, Regis Donovan, Kip Manley, Kevin Fitzpatrick, Michelle Denise Norton, John Picacio, Andrew Liptak, Tim Pratt, Niki Hyde, Tristan Salazar, Tim Maughan, Mandy Bu, SteveDave, Michael Moran, Saladin Ahmed and everyone else who offered suggestions.