To make black JELL-O, combine grape and orange flavors of JELL-O gelatin. The proportions are three packages or 9 ounces of grape flavor to one package or 3 ounces of the orange flavor.
To prepare black JELL-O, add these two flavors of gelatin to a bowl or pan with 3 cups of boiling water. The gelatin should dissolve completely in the water. Pour this mixture into a 13 x 9-inch pan and place it into the refrigerator for approximately 3 to 4 hours or until it sets up completely.
An optional way to make black JELL-O is to add a few drops of black food coloring to one package of strawberry gelatin. Black JELL-O is a commonly used color for Halloween jiggler snacks.