The ornamental design for interlockable toy character, as shown and described.
FIG. 1 is a front perspective view of the interlockable toy character;
FIG. 2 is a rear perspective view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a rear view thereof;
FIG. 6 is a right side view thereof;
FIG. 7 is a top view thereof;
FIG. 8 is a bottom view thereof; and,
FIG. 9 shows the interlockable toy character interlocked with another interlockable toy character shown in broken lines and which does not form any part of the claimed invention.