The ornamental design for a crabnightlight, as shown and described.
FIG. 1 is a perspective view of a crab nightlight according to the present design;
FIG. 2 is a front view of a crab nightlight according to the present design;
FIG. 3 is a top view of a crab nightlight according to the present design;
FIG. 4 is a side view of a crab nightlight according to the present design;
FIG. 5 is a side view of a crab nightlight according to the present design;
FIG. 6 is a rear view of a crab nightlight according to the present design; and,
FIG. 7 is a bottom view of a crab nightlight according to the present design.
Surface shading is indicated to shade FIGS. 1-7 to clearly show the contour of three-dimensional aspects of the present design, and forms a part of the design claimed herein.