It’s a cat and a turtle put together.  To name this creature, Jordan was thinking of some portmanteau(s) (a portmanteau is two words combined to make a new word, ex. smoke + fog = smog).  He thought of “curtle,” which is too reminiscent of bad milk, and “cattle,” which is better but already a thing.  I like just plain “turtlecat” the most, probably because it works best when sung to the tune of the Spiderman/Spiderpig song.  Turtlecat, turtlecat, does whatever a turtle cat does, etc.

This drawing is dedicated to my turtle of 8 years, Gonzlato, and my duplex’s recently catnapped cat, Toni.