The ornamental design for the grass catcher, as shown and described.
FIG. 1 is a perspective front view of the grass catcher of the present invention.
FIG. 2 is a perspective side view of the grass catcher of the present invention.
FIG. 3 is a perspective rear view of the grass catcher of the present invention.
FIG. 4 is an elevation view of the grass catcher of the present invention.
FIG. 5 is the opposite elevation view of the grass catcher of the present invention.
FIG. 6 is the rear view of the grass catcher of the present invention.
FIG. 7 is the front view of the grass catcher of the present invention.
FIG. 8 is the top view of the grass catcher of the present invention.
FIG. 9 is the bottom view of the grass catcher of the present invention; and,
FIG. 10 is a view of the grass catcher of the present invention attached to a lawnmower.
The broken line showing of a lawnmower is included for the purpose of illustrating environmental structure only and forms no part of the claimed design.