Preheat oven to 400°F. Line a baking pan with parchment paper.
Mix together pretzels, melted butter, and 1⁄2 cup sugar.
Spread pretzel mixture onto prepared baking pan. Bake for 7 minutes.
Let pretzels cool, then break into pieces.
Beat together cream cheese and remaining 1⁄2 cup sugar until smooth.
Fold in drained pineapple and Cool Whip. Refrigerate for 1+ hours.
Before serving, mix in pretzel pieces. Enjoy!
Notes
Reserve some pretzels to sprinkle on top for extra crunch. Only mix in pretzels just before serving to maintain crispness.

I hope this formatted article and recipe helps explain how to make this irresistible pineapple pretzel fluff! Let me know if you need any other details.