Deformed Macbook Pro Battery | zenandjuice.com: "A series of Apple Macbook Pro batteries suffer from defects where they can become “visibly deformed”. Apparently, the battery cells start to go bad, and expand. Initially, my laptop started shutting down at 40%. Then I noticed the metal exterior wasn’t flush with the bottom of the laptop, and the plastic casing started cracking. Then it really started to go haywire. I called Apple, and they sent me a replacement battery."
deformed MacBook Pro batteries - Google Search: "29 Mar 2009"