Sharpie has combined the permanence of a pen with the erasability of a pencil with their new Liquid Pencil. The "ink" inside this pen is a liquid graphite that stays erasable for three days. After that, it turns to ink and stays permanent.
Are you thinking what I'm thinking? If you're thinking, "holy shit, how can I use this to forge documents and steal from old ladies?" you are! Well -- did you come up with anything? Oh, OH --- I've got it!:
Please sign below to claim your bingo prize.
Then after they sign it we erase all the writing and replace it with, "All your property are belong to us". BOOM -- we're rich! But just in case, plan B: you club them with a sockful of Buckyballs and I steal the money from under their mattresses.