Preparation

• Preheat oven to 350 degrees F (175 degrees C).
• Combine flour, baking soda, salt, and baking powder in a large bowl. Mix with a fork until well blended.
• Beat butter, white sugar, and brown sugar with an electric mixer in a separate large bowl until smooth and creamy. Beat in eggs and vanilla extract until smooth and fluffy. Add flour mixture, 1 cup at a time, and mix with a spatula until well incorporated: fold in 1 ½ cups chocolate chips.
• Drop rounded spoonfuls of dough onto ungreased baking sheets, spacing them about 2 inches apart. Gently press 3 to 4 chocolate chips into the surface of each cookie, tip-side down, to form the spider 'bodies'.
• Bake in the preheated oven until edges are golden, 10 to 15 minutes. Cool on the baking sheet briefly, about 1 minute, before removing to a wire rack to cool completely.
• Melt remaining chocolate chips in a microwave-safe glass or ceramic bowl in 15-second intervals, stirring after each interval, 1 to 3 minutes. Fit a piping bag with a coupler and small tip. Drop piping bag into a tall glass and fold edges down around the glass. Spoon chocolate into the bag. Gather edges and twist together: draw little spider legs on each side of the spider bodies on cooled cookies.