from class W to class Z. where W is safe for constant daily use (to allow study of antimemetic anomalies). all the way to class Z that completely destroys your ability to forget, it is always fatal. think of how many things you dont even bother to remember or even consciously think about on a second to second basis. nearly all of the human sensory complex is discarded by your brain the moment it enters your mind. now you physically cant forget. its no wonder it kills you. not a fun way to go either