We claim the ornamental design for an incense burner, as shown and described.
FIG. 1 is a perspective view of an incense burner;
FIG. 2 is a top view of the incense burner of FIG. 1;
FIG. 3 is a side sectional view of the incense burner of FIG. 1;
FIG. 4 is a bottom view of the incense burner of FIG. 1;
FIG. 5 is a front view of the incense burner of FIG. 1;
FIG. 6 is a rear view of the incense burner of FIG. 1;
FIG. 7 is a side view of the incense burner of FIG. 1; and,
FIG. 8 is a side view of the incense burner of FIG. 1 opposite to the side view of FIG. 7.
In the drawings, the broken lines depict unclaimed portions of the incense burner. The dot and dashed lines represent a boundary between the claimed and the non-claimed portions and form no part of the claimed design.