OBJ is a file format for describing 3D shapes of things, e. g. for 3D printing. A .obj file contains data lines that define coordinates of points, corners and colors of polygons, curved surfaces, etc.

Today I learned that version 3.0 of the OBJ format may include lines like this:

csh <command>

Executes the requested UNIX <command>.

Sigh. Have we learned nothing since the Morris Internet Worm?

https://paulbourke.net/dataformats/obj/