File:Crysknife concept art (third variation) for Dune (2021) by Keith Christensen.jpg

Summary
Concept art of a Fremen crysknife for Dune (2021), by Keith Christensen.

Keith's commentary: "With all of these, we were playing with the idea of using the curvature of the tooth to create a knife that hugged the contour of the hip."

Source: Keith Christensen's ArtStation.com profile - "My Dune crysknife designs"