Colton: So Mulder, what do you think? Does this look like the work of little green men?
Mulder: Gray.
Colton: Excuse me?
Mulder: Gray. You said green men. A Reticulan skin tone is actually gray. They’re notorious for their extraction of terrestrial human livers - due to the iron depletion in the Reticulan galaxy.
Colton: You can’t be serious.
Mulder: Do you have any idea what liver and onions go for on Reticula?

1.02, “Squeeze”