However, some information about its appearance can be gleaned from the film's dialogue:
* Winston Zeddemore describes the ghost as "a big, hairy, green thing".
* Peter Venkman adds that it is "a nasty, nasty thing" and "has the smell of dead books".
Based on these descriptions, the Librarian could be imagined as a large, green, hairy creature, potentially resembling a demonic or grotesque human form. The reference to "dead books" implies that it might be covered in mould, dust, or decaying paper, adding to its ghastly appearance.
It's important to note that this is purely speculation, as the Librarian's true form remains unseen in the movie. Its appearance is left to the imagination of the viewers.
There are some fan-made illustrations and representations of the Librarian, which can be found online. However, these are not official depictions and vary widely in their interpretation of the character's design.