For some ineffably geeky reason I know the background on this. The video is from an aquarium--in Seattle, I think--which was having a problem with a rash of mysterious shark deaths. It was only after they set up a videocamera to monitor the exhibit after hours that they discovered the octopus was the culprit.

Before this incident, I don't think anyone even knew an octopus could kill a shark. For that matter, it still hasn't been documented elsewhere. It may be that this particular octopus just has a powerful dislike for sharks.

I still think the footage of an Orca whacking a Great White off the Farallons, while maybe not as surprising, is far far cooler.