Add the instant vanilla pudding mix and cold milk to a large mixing bowl.

Whisk the pudding mix and cold milk together for about 2 minutes until smooth and thickened. The mixture should look like a soft pudding.

Gently fold the thawed whipped topping and vanilla extract into the pudding until smooth, creamy, and fluffy. Use a rubber spatula and a light hand to avoid deflating the whipped topping.

Reserve a small handful of chopped Snickers and about 1 tablespoon of roasted peanuts for garnish. Fold the remaining Snickers, mini marshmallows, and peanuts into the creamy mixture.

Reserve about 2 tablespoons of caramel sauce for topping. Drizzle the remaining caramel sauce over the dessert.

Make a few gentle folds through the mixture to create visible ribbons of caramel without completely blending them in. This creates pockets of caramel flavor.

Cover the bowl and refrigerate for at least 1 to 2 hours until thoroughly chilled and slightly firmer. You can chill it overnight if you want to make it ahead.

Transfer the chilled fluff to a clean serving bowl or spoon it into individual dessert cups.

Top with the reserved chopped Snickers and roasted peanuts, drizzle generously with the remaining caramel sauce, and serve chilled.