Bake cake in 9x13 size pan from directions on box. 

When the cake is almost done, mix together the sweentened condensed milk and 1/2 the jar of caramel ice cream topping.  After taking the cake out make slits all over the top of the cake.  Then pour the mixture over the slits.

Break apart two of the Skor bars.  (I usually use a hammer, but be careful of not busting the packaging.)  Then sprinkle them over the top of the hot cake.

Let cake cool for at least 30 minutes.

After cake is cooled, spoon on cool whip for the icing.  Once done, pour lines or designs with the other half of the jar of caramel topping.  Crunch up last two Skor bars and sprinkle them on top.

Then enjoy.  This dessert must be refridgerated.