Production of Jell-O 1-2-3 stopped in 1996, but here is a DIY version of the treat from the Jell-O Gallery. http://www.jellogallery.org/
Pour boiling water into blender and add gelatin. Cover and blend at low speed until gelatin is completely dissolved (about 30 seconds). Combine cold water and ice cubes to make 1 1/ 4 cups. Add gelatin and stir until ice is partially melted. Then add Cool Whip; Blend at high speed, about 30 seconds. Pour into dessert glasses. Chill about 30 minutes.
Dessert layers as it chills.
Yield: 4 servings