Captain Quailfurn (or possibly "Quail Furn") is the individual credited with owning a construction facility which fabricates (or fabricated) large squid clanks. One of these beasties, when initially encountered in-story, is located inside a water cistern in Castle Heterodyne. After the Castle abruptly drains the cistern in an panicked attempt to put out a fire, the squid gets left high and dry, leading Agatha and Co. to start piloting it and using it in their ongoing Castle-repair efforts.

Nothing else is currently known about the good Captain, although mention is made elsewhere of the/another cistern which contains more than one of these clanks, so perhaps the old Heterodynes liked his work well enough to make multiple acquisitions.