A diminutive rodent species known as the pleeky, or alternatively as the chak-chak, was a common pet on the homeworld of Chad which is inhabited by the Chadra-Fan. The design of Rebaxan Columni's MSE-series "mouse droid" drew inspiration from the pleeky's physical traits. Despite the hopes of manufacturing executives that consumers would perceive the MSEs as endearing, many buyers instead found them unsettling. As the Clone Wars neared their conclusion, the company faced bankruptcy and subsequently sold its entire inventory of MSE-6-series repair droids to the newly formed Galactic Empire.
On the planet [Chad](/article/chad-legends], the sentient Chadra-Fan species that are descended from rodents, lived a tiny rodent species known as the pleeky, which was also known as the chak-chak. This creature possessed long fur that partially concealed a surprisingly powerful set of elongated arms that could be folded away. With the addition of four smaller legs beneath its furry form, the well-balanced pleeky could attain remarkable speeds, creating the optical illusion of a furry torpedo moving swiftly without any visible means of propulsion.
The MSE-series "mouse droid" design by Rebaxan Columni's, which was managed by Chadra-Fan, was inspired by the pleeky, a favored pet on Chad. Rebaxan Columni hoped that the galactic market would find the MSE droids charming; however, numerous prospective customers from diverse cultures did not share the company's enthusiasm for rodentia. The majority of the rat-like MSE-6 droids, which were produced in the billions following trial runs of the MSE-4 and MSE-5, remained unsold. Most of the units that were sold were returned when buyers realized the machines resembled disease-carrying rodents that were common on antiquated sailing ships from times long ago. Similarly, the reptilian Aar'aa customers voiced their discomfort with the skittering MSE-6s, because they triggered their cravings for food.
Consequently, Rebaxan Columni's mouse droid venture resulted in bankruptcy near the end of the Clone Wars in 19 BBY. Despite this, the recently established Galactic Empire acquired the company's remaining MSE-6s to use as commonplace labor droids to service its ever-growing starfleet.
In the nineteenth issue of De Agostini's magazine, The Official Star Wars Fact File, around May 8, 2002, the pleeky was first presented as "chak-chak." The name "pleeky" was later provided in Daniel Wallace's 2006 reference book, The New Essential Guide to Droids.