Imagine a fundamental building block of life as a gear. Now imagine your brain as a clockwork clock. Now take the diseased prion gear and throw it into your clockwork mind.

Suddenly, that mismatched gear smashes into the other gears. This strips the gears and makes them like the foreign gear and now your mind no longer keeps track of time and many other things.

https://en.m.wikipedia.org/wiki/Prion

Two Hunters from the Same Lodge Afflicted with Sporadic CJD: Is Chronic Wasting Disease to Blame? (P7-13.002) https://www.neurology.org/doi/abs/10.1212/WNL.0000000000204407

Deer Are Beta-Testing a Nightmare Disease https://www.theatlantic.com/science/archive/2024/02/deer-chronic-wasting-disease-prions-spillover-people/677307/ https://archive.is/ryj69

If i remember right a simplified explanation would be: A protein is a long chain of amino-acids that folds into a specific structure to achieve a certain task(for example stuff like cut a certain bond in a certain molecule). Prion is the exact same chain of amino-acids but it has folded in a wrong configuration thus cannot complete the original function, and even worse it can refold other proteins with the same amino-acid chain to the prion configuration slowly spreading through the body infecting more and more proteins ultimately depriving the body of the ability to do a specific fuction

Pls someone correct me if im wrong because my source is a vague memory of likely a video i dont remember possibly years ago.

Prions ,as explained on a different comment above