So I had posted earlier a video about the grues from "Zork".
"Zork" was a text adventure from the masters of the genre at Infocom. I never played it, instead playing "Apple Adventure" which was apparently similar. The difference was that in "Apple Adventure" when your torch or lamp went out you were likely to fall down a hole. In "Zork" if you entered darkness, or your light source went out, you were likely to be eaten by a grue.
Now, this was a text adventure. No one knows what a grue looks like. First, they were never shown, it's a text adventure after all. Then of course they they only came out in the dark, and were seemingly terrified of the light.
So I'm thinking all of this while I'm describing the game and grues to Jennifer over dinner, and it hit me.
The movie "Pitch Black" takes place on a planet populated entirely by varying species of grues.