We've scoured the series and films for cameos that were truly shocking. These include guest-starring roles, but Idris Elba- or Kirstie Alley-sized lead parts (or regularly recurring, Whoopi Goldberg-esque gigs) were not considered. The motto was: the more random, obscure and harder-to-spot, the better.
Here's our look at the jaw-droppers, the Trek stars who made us sit up and go, "Wait, what are they doing here?!"
Photo Credits: The CW; John Paul Filo, CBS; Ron Batzdorff/NBC; George Kraychyk/Hulu; NBC, Peter Kramer/NBC; NBC; Gregg DeGuire/Getty Images; Jason LaVeris, FilmMagic; NBC, Chris Haston / NBC; Chris Haston/NBCU Photo Bank/Getty Images; Vivian Zink/Getty Images; Bill Records/NBC via Getty Images