Line 13x9-inch pan with foil. In medium bowl, combine crust ingredients; mix well. Press in bottom of foil-lined pan. Freeze 20 minutes or until chilled.
Spread 1 cup of the fudge ice cream topping over crust. Freeze 30 minutes or until firm.
In large bowl, combine ice cream and marshmallows; spoon and spread over fudge topping. Cover; freeze at least 4 hours or overnight until firm.
Place remaining 1/4 cup fudge topping in decorating bag with writing tip or in small resealable plastic bag with one tiny corner cut off. Pipe desired message on ice cream. Return to freezer.
To serve, drizzle or serve with caramel ice cream topping.