The ornamental design for a bathtoy, as shown and described.
FIG. 1 is a front and top perspective view of a bath toy, showing my new design;
FIG. 2 is a rear and bottom perspective view thereof;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a left side elevational view thereof;
FIG. 6 is a right side elevational view thereof;
FIG. 7 is a top plan view thereof;
FIG. 8 is a bottom plan view thereof; and,
FIG. 9 is an enlarged view of the portion indicated with numeric 9 in FIG. 1.
The broken rectangle denoting the area of enlargement in FIG. 1 forms no part of the claimed design. The dashed broken lines in the figures illustrate portions of the article that form no part of the claimed design.