I forget where I heard this but someone mentioned that a 4-dimensional being could mirror you. Doesn’t sound so bad until you realize your amino acids & stuff would all be the opposite chirality, which means you could no longer process food.
This, the mirroring part, also happens in an Arthur C. Clarke short story: https://en.wikipedia.org/wiki/Technical_Error
Mass Effect has a similar idea. There are species that eat levo foods and ones that eat dextro foods.
Heh, eating isn’t the only time they have to worry about protein absorption.
There’s a great YA book about this: https://en.wikipedia.org/wiki/The_Boy_Who_Reversed_Himself?wprov=sfla1