Preheat your oven to 350 degrees F and grease a 9-inch x 13-inch cake pan.
Combine the chocolate cake mix, chocolate fudge instant pudding mix, sour cream, vegetable oil, milk, eggs, vanilla extract, and salt in a large mixing bowl and blend on high until smooth.
Pour the batter into the prepared cake pan and bake for 28-32 minutes.
After baking, let the cake cool in the pan for 30 minutes.
Poke holes all over the top of the cake using a wooden spoon handle.
Whisk together the chocolate pudding mix and 2 cups of milk for about 2 minutes until it thickens; pour over the cake.
In a separate bowl, whip the heavy cream, powdered sugar, and chocolate pudding mix until thick and fluffy.
Spread the frosting over the cake evenly.
Crush Oreo cookies and sprinkle them over the frosting.
Write 'R.I.P.' on Milano cookies with black gel icing and insert them into the frosting as tombstones.
Decorate with ghost Peeps and candy pumpkins.
Serve and enjoy your Halloween Graveyard Chocolate Poke Cake!
Notes
Use room temperature ingredients for a smoother batter. Chill before serving for better flavor melding.