First, I'm not sure it this is the appropriate place for this, but since it's fairly general and I wasn't sure where else it would fit, I figured this would be the best choice.
Here's the link:
Meet the world’s only immortal animal | ZME Science
They're called turritopsis nutricula (doesn't look like there's a common name yet) and closely related to jellyfish. I didn't really understand why it works, but something to do with the way their cells operate makes it so they don't die of old age, which is the sense the article uses the word immortal in. So yes, they can still be killed in other ways, but they supposedly have the potential to live forever due to the way they're designed.
Either way, I thought it was pretty cool.