How about a mind altering book that will an actual tumor in the brain of anyone who reads it. The tumor then mind controls the reader to go on a murderous rampage while making the person think they are in a wonderland of fun and amazement.
Link to the sandbox page: http://scp-sandbox-3.wikidot.com/beertaster
I'm open to suggestions like
What if the tumor is an egg that hatches into a brain eating Pixie and flies away to a colony of its carnivorous kind and lure children to their hive?
Or what if the tumor teleports people to the lair of a giant multidimensional psychic spider that feasts on memories.
So I'm open to changes.