The ornamental design for a self-propelled carousel toy, as shown and described.
FIG. 1 is a front isometric view of a self-propelled carousel toy in accordance with the new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a left side elevational view thereof;
FIG. 4 is a right side elevational view thereof;
FIG. 5 is a rear elevational view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The dashed broken lines are included for the purpose of illustrating features of the self-propelled carousel toy that form no part of the claimed design.