My Logitech Mouse.... Melted?!?!?!

So put my mouse on the charger and went to work the other day and came back to THIS:

 And this isn't the first I've heard of this, there have been a few reports of this online. It looks more like an issue with the batteries than the mouse, but it's unnerving none the less. I own several Logitech products, 2x mxduo, mx1000, 3 wireless pc gamepads, wireless headset for my xbox, bluetooth headset... this experience really is making me reconsider these other purchases.

I know it's not much of an article, but it's something i thought should be shared as it is a safety concern that not many people know about.

03/10/2007
EDIT:

Since a lot of people have been commenting about misuse and trying to recharge alkalines and stuff, i will add in, that these were the ORIGINAL batteries supplied with the mouse, they ARE rechargeables i had used the mouse for about 2 years prior to this with no issues. And it is an MX700 (Part of the MX Duo).