In advance: Make cookies. Prepare and roll out dough. Cut cookies using dinosaur cutter. Bake and cool.
Use full strength icing to pipe tip 3 outline; flow in with thinned icing. Use lighter shade of thinned icing to immediately add assorted tip 2 dots for spots. Let dry on waxed paper-covered boards. Use full strength icing to pipe tip 3 dot eye and tip 2 pupil.