Grease a 2 x 4 inch mini-loaf pan and set aside. Empty the marshmallow fluff into a medium-sized bowl, add the green food coloring and mix with a fork until well blended and consistent in coloring. Set aside.
Using a double boiler, melt the chocolate over the boiling water and then remove from heat. Pour 1/4 Cup of the melted chocolate into the greased loaf pan and spread until the surface is even. Sprinkle 1 teaspoon of the crushed pecans over the melted chocolate and place the loaf pan in the freezer for 10 minutes to solidify the lower layer of the Reptar Bar.
Remove the pan from the freezer and drizzle about 1 tablespoon of the green marshmallow mixture in the center of the bar, spreading it vertically but making sure that there is at least 1/2 inch of chocolate space surrounding all sides of the marshmallow. If you don't do this, when you add the top layer of the chocolate the marshmallow will not be encased and it will look like my first unsuccessful attempt at a Reptar Bar, as seen in the photo in the blog post. Sad, isn't it?
Then drizzle the teaspoon of caramel over the marshmallow and take the bar back over to the pot of chocolate, which should still be melted. Using a spoon, first drizzle the chocolate around the green marshmallow heap to encase it in a chocolate wall, then drizzle just enough chocolate over it so that the green part is covered. If you do this in the opposite order, the weight of the melted chocolate on top of the marshmallow will force it to the sides, once again making a messy Reptar sandwich instead of a nice enclosed Reptar Bar.
Place the Pan in the freezer for another 10 minutes, or until the chocolate has solidified. Gently press the sides of the pan in and out to loosen the bar, then flip the pan over onto a plate and shake it until the bar falls out. Repeat this process until all of the chocolate has been used, will make about 4 Reptar Bars. Store them in a cool, dry place.