The ornamental design for a slap hammer, as shown and described.
FIG. 1 is a bottom perspective view of a slap hammer in accordance with the new design;
FIG. 2 is a top perspective view of the slap hammer of FIG. 1;
FIG. 3 is a bottom end view of the slap hammer of FIG. 1;
FIG. 4 is a top end view of the slap hammer of FIG. 1;
FIG. 5 is a left side view of the slap hammer of FIG. 1;
FIG. 6 is a right side view of the slap hammer of FIG. 1;
FIG. 7 is a front side view of the slap hammer of FIG. 1; and,
FIG. 8 is a rear view of the slap hammer of FIG. 1.
The broken lines shown in FIGS. 1-8 illustrate portions of the slap hammer that form no part of the claimed design. The broken lines shown in FIGS. 1, 2, and 5-8 directly adjacent to the left and right sides of the central area illustrate the boundary of the claim.