In medium saucepan over low heat melt the marshmallows in the milk. Set aside to cool thoroughly. When cool add the creme de menthe, creme de cacao, and whipped cream.
Crush the chocolate cookies with the butter, this can be done in a plastic bag with a rolling pin. Press the mixture into a pie plate to make crust, the cookies should form the banks of the pond. Pour filling into piecrust and chill in the refrigerator
Decorate by placing sprigs of herbs around the sides of the pond. Then place a plastic pond critter in the center of the pie.
Decoration: a few sprigs of herbs such as fennel, basil, rosemary, etc, for pond foliage .
Decoration: a small plastic frog, snake, turtle, or duck.