I was bored so I made an usb flashdrive that looks like wall adapter.
You will need:
*Some electrical tape
First, open the wall adapeter using your knife. (Or a screw driver if it´s secured with screws).
Then get rid of everything that was inside the wall adapter. Make sure you cut the wires coming from the connectors that plugs into your wall so if someone tries to plug it she will not get killed.
Next you cut the wire coming from the adapter and take off that rubber thingy that secures that wire in it´s place.
Push a screw driver through that rubber thing to make the hole bigger and then try to get your usb cord through it.
Open your usb memory, desolder the connector, strip your wires and solder them where the usb connector was.
[ _ _ _ _ ] <-- Usb connector in your wire looks like this. From left to right there is Ground(Black wire), Data -(Green wire), Data +(White wire and Power +(Red wire).
Use the superglue to glue the flashdrive inside the adapter, rubber thing on the wire and to hold everything together.
"As long as the pins are properly isolated and insulated, you could use this to store important data, leave it plugged into a socket anywhere in the house, and if your PC gets stolen, they might pick up any thumbdrives lying around, but they're unlikely to take what looks like a spare charger plugged into a random socket..."