Combine dry ingredients: Whisk cornstarch, cocoa powder, and granulated sugar in a medium saucepan.

Mix in soy milk: Gradually pour in soy milk, mixing continuously until smooth.

Heat the mixture: Place saucepan over medium heat, stirring constantly until it bubbles and thickens.

Distribute into cups: Spoon pudding into cups, fill three-quarters full, and cool before refrigerating.

Prepare candy pumpkins: Form pumpkin shapes from filling of cookies and insert pretzel pieces.

Crush cookies for topping: Crush remaining cookies and set aside for decoration.

Create tombstone garnishes: Break graham crackers into shapes resembling tombstones.

Assemble and chill: Layer crushed cookies on pudding cups, add tombstones, and chill until ready.