Goodbye duvet cover. Even after swimming around in water and me trying to work with it in the water (I will keep the suggestion by @elbutterfield in mind for less extreme cases), it wouldn't untwist. I chopped it up. Inside were the following:
Two bath towels
Three pillowcases
Two hand towels
One dishtowel
Two dryer sheets
hahaha. i just saw the duvet cover as a shark swallowing all that laundry 🤣🤣🤣
my metaphorical mind is active today 😎