At the last Profiles in History auction, lot # 682 was a set of Ceti Eel Concept Art. It was an interesting collection and worth a look.
The Ceti Eel on screen
The patent drawings for the Ceti Eel. Yes! They are patented!
Lot # 682
Archive of Ken Ralston “Ceti Eel” concept sketches and related production materials from Star Trek II: The Wrath of Khan. (Paramount, 1982)
A comprehensive 22-piece collection of concept art and correspondence related to the “Ceti Eel” from Star Trek II: The Wrath of Khan, including: a series of (15) Ken Ralston (5 time Academy Award-winner for visual FX) full color concept sketches in artist pen and ink on 6 x 14 in. paper for a variety of “Ceti Eels” (1) typed letter signed by Ken Ralston, on Lucasfilm stationery, accompanied by (2) hand-drawn illustrations of the “Ceti Eel” practical effect mechanics. (1) copied inter-communication memo from producer Robert Sallin to crew with (1) Xeroxed copy of an illustration showing a “Ceti Eel” dropping out of “Chekov’s” ear, and, (2) polaroid photos of the practical “Ceti Eel” embedded in a latex ear. All materials in production-used, good condition. From the collection of Star Trek II: The Wrath of Khan producer Robert Sallin who created the concept of the “Ceti Eel”, directed the creation of these sketches and ultimately chose the final version of the Eel that appears in the film. Accompanied with a signed LOA.