Terrifying! The YouTube link is OK, but see the full-size, high-frame-rate Quicktime version on nature.com to see this rare animal in all its lit-up glory. Like something out of a James Cameron movie....

Remains of Taningia danae often show up in the stomachs of sperm whales. The squid's flabby flesh led experts to think that it floats in the water column like a neutrally buoyant scuba diver. But the new footage shows it can reach speeds of up to 9 kilometres per hour.

When presented with bait, the squid attacked, flashing its luminescent spots, or 'photophores', which contain glowing bacteria. It produced longer glows when faced with the bait rig's lights, suggesting that it was performing some sort of mating dance.

That's pretty amazing.

-Eagle