Trek's Orion Slave Girl + 28 more of our favorite monochromatic aliens

The great thing about aliens is they can be any color you like.

Somewhere along the way, sci-fi creators started to embrace this fact and gave us things like the sexy green Orion Slave Girls from Star Trek and the bright orange Carrot Man from Lost In Space. From there, the floodgates opened, and now we have a veritable rainbow of alien species across the genre, from the classic "greys" to bright blue opera singers to a bright red lobster doctor. 

So to celebrate the broad color palette of sci-fi's many visitors from space, we devoted the latest in our series of features inspired by Syfy's Defiance to some of our favorite monochromatic aliens.