I claim the ornamental design for a plush toy, as shown and described herein.
FIG. 1. Is a perspective view of my plush toy design;
FIG. 2. Is a front view thereof;
FIG. 3. Is a rear view thereof;
FIG. 4. Is a left side view thereof;
FIG. 5. Is a right side view thereof;
FIG. 6. is a top view thereof; and,
FIG. 7. Is a bottom view thereof.
The broken lines in the drawings show environment that forms no part of the claimed design. Applicant makes no claim as to color with regards to the present invention.