Combine 1/2 cup sugar, melted butter, and crushed pretzels. Stir, place in a 13 * 9 baking dish covered with parchment, press, bake for 7 minutes, then cool.
Whisk remaining sugar with cream cheese until creamy.
Add chopped drained pineapple, then whipped topping, and stir.
Break up the caramel pretzels, add most to the mixture, sprinkle the rest on top. Cool in the refrigerator for 1 hour and serve.