Hubcap

A hubcap was a home or structure that functioned as a habitat for members of Kaat Thrick-Thrick's species. At least three families could fit in a hubcap.

Behind the scenes
Hubcap was mentioned in a segment named "The Seminar Participants", written by Bob Carrau for the 1993 book Monsters and Aliens from George Lucas, a publication that collects concept designs and photographs from various George Lucas projects. Lucasfilm employee Leland Chee, who maintains the Holocron continuity database, has indicated that information contained in the book is non-canonical.