Room Defender.

Ah, the ultimate toy sentry to defend your precious room and properties:

Room Defender - An automated motion sensor sentry detterent, capable of shooting up to 16 foam disks at any intruder that enters your bedroom or office.
Load the disks set the direction you want the sentry to fire at, arm the room defender ...

It will detect any motion and blast anyone that comes into your room/office.

http://www.gadget-box.com/product_info.php?ref=7&products_id=4064 - via Gizmodo