A jefflac was a type of being originating from the galaxy. During an incident where J-Squadron, a Resistance team, found themselves amidst a stampede of animals escaping rancors on the world of Vodran, they were sometimes bumped by a stray jefflac or an awkward dewback. These animals were abandoned on the planet by Harra, a Hutt who used to run an exotic animal trade there.
The first appearance of jefflacs is in Join the Resistance, the initial book in the Star Wars: Join the Resistance series written by Ben Acker and Ben Blacker. This book, aimed at younger readers, is set during the conflict between the Resistance and the First Order and was released on March 7, 2017. The creatures' role is limited to brief mentions.