Vulcan marsupial

From Memory Alpha, the free Star Trek reference.

The Vulcan marsupial is an animal native to Vulcan.

When the Doctor from the USS Voyager was trying to find a cure for his creator's illness, Doctor Lewis Zimmerman manipulated the Doctor's tricorder so that it would display a mitochondrial scan of a Vulcan marsupial. It took the Doctor a full hour to find out what was wrong with the scan. (VOY: "Life Line")