Man, I've been lurking for a looooong time, but I've recently come up with an idea that I think is fairly novel, or at least distinct enough to be interesting.
A page with the sentence "Sometimes you need a change of Perspective." Printed in the center. The page itself appears to have come from a book, with one side being torn and frayed as if ripped out with a margin of care. The page's properties begin the moment a reader is no longer observed by any means, by it physically watched, by camera of any kind, or anything else you could care to think about. Once not observed the reader is transformed randomly, with changes being as minimal as becoming a man who has lost a leg or a leper, to becoming a dairy cow, to a fax machine missing its power cable. Its important to note that these people are not taking on another form ,they are completely replaced, that man missing his leg was not the D-class who had just read the page, he is Bob, an electrician who has lived with his disability for decades.
After a period of time ranging from a day to an hour, once left unobserved the transmuted individual will return to normal. They will have no memory of what had happened except for a feeling of compassion and understanding, and a certain level of fondness or 'respect' to a group or condition or object based on what they were turned into. The man who became Bob is very nice and respectful to disabled people now, even if before he was an utter psychopath. The transformations do not necessarily relate to the person, but they can often have an affect on that person which makes them nicer, more docile, or more proactive and positive. Sometimes they have new phobias or are constantly terrified. These changes persist even through the use of Amnesiacs. People, when returned, often have notes on their person, ranging from letters to crumpled up notes, that contain enigmatic comments that might not seem to mean anything at all and are always out of context, i.e. for Bob he can have a note saying, "Walking up hill would have been murder." The D-class would recognize the writing on the note, but not remember its significance or the context behind it.
Except, of course, if someone is transformed into a corpse. That's perhaps a little too much perspective for anyone.
Extra details: The page is simple paper, though it looks like it was made with a typewriter the actual paper is colored black for the text: There was no ink used. The page can be burned, torn, and have pieces severed from it, but once unobserved would return to its former state, pristine and unmolested.
Considering this is my first SCP proposal, I readily encourage everyone and anyone to tear into my idea. Thanks!