In large bowl, stir ice cream and chopped candies just until blended. Spread evenly in ungreased 13x9-inch pan. Cover; freeze at least 8 hours or until firm.
Heat oven to 350°F. Crumble cookie dough into medium bowl; knead in chocolate chips until blended. On well-floured surface, roll half of dough to 1/4-inch thickness. Cut with floured 3x2 1/2-inch skull and crossbones-shaped cookie cutter. Place 2 inches apart on ungreased cookie sheet. Repeat with remaining dough.
Bake 8 to 10 minutes or until lightly browned. Cool 5 minutes; remove from cookie sheets to cooling racks. Cool completely.
In small bowl, mix powdered sugar and water until smooth. Spread or pipe glaze onto 8 of the cookies to look like skull and crossbones. With black icing, pipe eyes, nose and mouth. Cut out 8 ice cream shapes with skull-and-crossbones cutter. Place on bottoms of 8 plain cookies. Top with decorated cookies, flat side down; gently press together. Wrap in plastic wrap; store in freezer.