Preheat your oven to 350 degrees F (175 degrees C) and prepare a 9x13-inch cake pan by greasing it lightly.

In a large mixing bowl, combine the chocolate cake mix, chocolate fudge pudding mix, sour cream, vegetable oil, milk, eggs, vanilla extract, and salt. Mix until well combined, about 2 minutes.

Place the pan in your preheated oven and bake for 28-32 minutes until a cake tester comes out clean.

Remove the cake from the oven and allow it to cool in the pan for about 30 minutes.

In a separate bowl, whisk together the chocolate instant pudding mix and 2 cups of cold milk for about 2 minutes until it starts to thicken.

Spread the prepared chocolate pudding over the top of the cake, ensuring it fills all the holes.

In a large bowl, combine heavy cream, powdered sugar, and the chocolate pudding mix. Whisk until thick and fluffy.

Generously spread the frosting over the entire top of the poked cake.

Using a food processor, pulse the Oreo cookies until they turn into fine crumbs. Evenly sprinkle these crumbs over the frosting layer.

Take the Milano cookies and use black gel icing to write 'R.I.P.' on each one. Press these cookies into the frosting to create tombstones.

Gently press the ghost Peeps into the frosting and arrange the candy pumpkins around for decoration.

If desired, sprinkle Halloween-themed sprinkles over the cake before serving.