Half a kilometer under the Gulf of Mexico, you can expect to find life, small life. Jellies will float by and a silvery fish may dart from view, but you aren’t likely to spot a giant. It was incredible luck then, when the remotely operated underwater vehicle (ROV) Hercules, deployed by the 2015 Nautilus Mission, encountered a very inquisitive sperm whale.

These behemoths are hard to come by. Because they can dive deep (almost five times deeper than the depth of this meeting) and for long amounts of time, sperm whales are seen relatively less often than other whales. Their absence from our cameras doesn’t mean they’re loafing around the dark depths — when we do get a glimpse of these mammals, they often bear the scars of epic undersea battles with giant quid in the form of sucker spots and scrapes. If you look closely, it appears that this specimen has had its fair share of calamari too.

The researchers’ reactions in the video above are perfect. As the whale apparently stares at and explores the glowing stranger, scientists exclaim and remark to each other like it’s their first dive. The footage really is stunning.

To follow the Nautilus expedition live, dive in here.