Plug in this USB doll, set up your Skype, Yahoo or MSN client, and when your friends IM you, he hits himself on the head with a hammer. Feel free to tape a new face on him, so a relevant party receives the pain with each lolcat link that gets passed to you. You can also patch the i-Knock with custom MP3s to play for extra special IM-ers. [Stysen via Slippery Brick]