- Bake the chocolate cake according to the box instructions in a 9x13 inch pan. Let it cool for 10 minutes. 
- Use the handle of a wooden spoon to poke holes all over the cake. 
- Whisk together pudding mix and milk until smooth and pourable. Pour over the cake, making sure it seeps into the holes. 
- Sprinkle mini marshmallows over the cake and gently press them in. 
- Spread the whipped topping evenly over the cake. 
- Sprinkle crushed graham crackers on top and drizzle with chocolate syrup. 
- Chill for at least 2 hours before serving. Slice and serve cold!