Klingon lice
According to the final draft script of the  first season episode , Klingon lice were a type of minuscule lifeform common in Klingon living environments that could remain on a person's body after they had left that area.

Klingon lice were mentioned once only in a speech Doctor Phlox was scripted to make to the members of a landing party – a Vulcan and two Humans – who were in 's decontamination chamber after returning from the . Phlox told the newly returned officers, "Aside from a predictable complement of Klingon lice, you have little to show for your stay on the Klingon ship." In canon Star Trek, however, Klingon lice have never been referenced nor shown.
Unused production material