In a large mixing bowl, combine milk and JELL-O Mousse mix. Mix on low speed for 30 seconds, then on medium speed for four minutes. Once finished mixing, set in refrigerator until ready to use.
Place one cup of JET-PUFFED Miniature Marshmallows and one cup of COOL WHIP Whipped Topping into microwave safe bowl, and microwave for 30 seconds. Remove from microwave and stir well, adding in the remaining COOL WHIP Whipped Topping.
If topping your jars in chocolate and graham cracker crumbs, pour approximately four tablespoons of chocolate sauce onto a plate, and dip the opening of your jar into the chocolate sauce, then into your crushed graham cracker mixture. Repeat with remaining jars.
Time to fill your jars, spoon approximately four tablespoons of graham cracker crumbs into the bottom of each jar.
Next spoon a layer of your COOL WHIP Whipped Topping and JET-PUFFED Miniature Marshmallow mixture into each jar, using approximately 1/2 cup for each jar.
Next spoon your JELL-O Mousse Mixture into each jar, using approximately 1/2-2/3 a cup of mousse into each jar.
Sprinkle additional graham cracker crumbs on top of mousse layer, followed by an additional scoop of COOL WHIP Whipped Topping and JET-PUFFED Miniature Marshmallow mixture. Sprinkle JET-PUFFED Mallow Bits on top and add a quarter sheet of graham cracker to the top for garnish (if desired, dip the graham cracker into the mousse and sprinkle with Mallow Bits).
Chill in refrigerator until ready to serve.