Rhubarb Dump Cake
["4 c. rhubarb, cut up", "1 small pkg. sugar-free jello", "1/2 c. sugar", "1/3 c. butter", "cake mix (white or yellow)"]
["Put in 9 x 13-inch pan.", "Sprinkle white or yellow cake mix over.", "Melt 1/3 cup butter; pour over cake mix.", "Pour 1 cup warm water over cake.", "Bake 45 minutes at 350\u00b0."]
["rhubarb", "sugar", "sugar", "butter", "cake"]