Using a mixer, cream the softened butter and both sugars together on medium speed until smooth. Add in the eggs, beating well after each one is added. Scrape down the sides of the bowl. Add the vanilla and peanut butter. Mix until well combined.
In a separate bowl, combine the flour, baking soda, baking powder and salt together.
Slowly add the dry ingredients to the wet ingredients and mix on low until well combined.
Cover dough tightly and chill for at least 3 hours and up to 2 days in the refrigerator.
Once dough has chilled, preheat oven to 350 degrees. Line your baking sheets with parchment paper or a silicone baking mats (optional). Place the chilled dough on the counter to soften a little while your oven is preheating.
Roll the dough into balls (about one tablespoon dough each). Place them two inches apart from each other on a baking sheet.
Bake them for 11-12 minutes or until edges are lightly browned.
Remove from oven and gently place two Whopper candies on top of each cookie. Press down slightly more on one of the Whoppers to resemble the spider's head.
Let them sit on the baking sheet for five minutes before placing on a cooling rack.
Once all the cookies are made and cooled completely, melt the chocolate chips.
Place about ¾ cup chocolate chips in a microwave safe bowl. Heat for 30 seconds and stir. Heat at additional 15 second increments and stir after each one until the chocolate is melted and smooth.
Place the melted chocolate into a decorating bag and using a writing tip, make the legs of the spider. Make four legs on each side of the Whoppers. Working from the center out, make two legs going towards the back and two legs going towards the front of the spider.
For the eyes, place two small dots of melted chocolate on the "spider head" Whopper and place a sprinkle on each dot of melted chocolate.
Let sit until the chocolate has set.
Store cookies in an air tight container for up to one week.