In a large mixing bowl, whisk together the all-purpose flour, unsweetened cocoa powder, baking soda, baking powder, and salt until well blended. In another bowl, combine room temperature eggs, buttermilk, plain Greek yogurt, canola oil, and vanilla extract, mixing until smooth. Gradually incorporate the dry ingredients into the wet, and gently fold in the cream soda until the batter is uniformly combined.

Preheat your oven to 350°F (175°C) while you prepare three 9-inch round cake pans by greasing and flouring them. Divide the chocolate batter evenly among the pans and smooth the tops for even baking. Bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean. Once baked, remove the layers from the oven and let them cool in the pans for 10 minutes before transferring to a wire rack to cool completely.

In a mixing bowl, beat 1 cup of softened salted butter until creamy and fluffy, about 3-5 minutes. Gradually add powdered sugar, about 1 cup at a time, mixing on low speed to avoid a sugar cloud. Then, incorporate cocoa powder and creamy peanut butter, adding melted chocolate while continuing to beat the mixture until you achieve a luxurious, fluffy frosting texture.

Start by placing one layer of the chocolate cake on a serving plate. Spread a generous layer of butterbeer frosting over the top, then drizzle with butterscotch sauce for added flavor. Repeat this process with the second layer, stacking it carefully before placing the final cake layer on top, ensuring it is aligned for a beautiful finish.

To make your Forbidden Forest Chocolate Butterbeer Cake pop with Halloween flair, top the cake with a spider web made from mini marshmallows. Arrange chocolate pretzel sticks to create charming spider decorations, and use crushed pretzel sticks for an added crunchy texture around the base, enhancing both the flavor and visual appeal of your delightful creation.