The Evil Mad Scientist folks have compiled an annotated bestiary of junk-mail envelopes that are camouflaged to look like important correspondence. It's a fascinating study in meatspace spam. Often times, these envelopes are quite well done. Above is an example that might cause a genuine double take— with its “FINAL NOTICE ENCLOSED“ — and bank-PIN style tear tabs on the sides... And then, there’s the fine print, so that you really take it seriously.