Preheat oven to 375~. Lightly grease a baking sheet. In a saucepan melt chocolate over low heat. Let cool. In a small bowl mix flour, baking powder and salt. In a medium bowl beat margarine and sugar until creamy. Stir in egg, vanilla and chocolate. Add flour mix and mix all well, forming a stiff dough. To make spiders, shape a 2" flat oval for the body. Make the spiders head by flattening a circle about 1/2" wide. Shape dough for 8 legs, each 2 inches long and less than 1/4 inch wide. Attach the head and legs to the body. Use red candies for the eyes. Bake in 375~ oven for 5-8 minutes. Let spiders cool on baking sheet to avoid breaking when removing.