Crush graham crackers in a plastic sandwich bag until they break into pieces about pea-sized. Avoid over-crushing—you don't want to end up with graham cracker powder. Divide equally into 4-6 small ramekins or small tea cups.
Make instant chocolate pudding according to the instructions on the box, and divide it equally among the ramekins. Tap ramekins on the counter to help release any air bubbles.
Place marshmallow fluff into a sandwich bag, and squeeze into one of its corners, and twist the excess bag to form a piping bag. Cut a small bit off the corner of the bag, and pipe marshmallow fluff onto the chocolate pudding. It helps if you start in the center of the cup, and pipe your way outward in a spiral.
Let sit for about an hour in the fridge to allow marshmallow to settle.
If you happen to have a cooking torch, “toast” the top of the marshmallow layer. If you don’t have a cooking torch, place all the ramekins on a baking sheet and put under your broiler as close as possible to the top on a high temperature setting with the oven door open until the marshmallow browns.