There are ordinary amphipods, known to be mostly tiny shrimp-like crustaceans that thrive in aquatic environments around the world, and now there are “supergiant” amphipods, which are 10 times larger and, frankly, quite freakish-looking (see video and photo).

British scientists made the remarkable discovery by accident while participating in a joint expedition with New Zealand scientists to probe the depths of the Kermadec Trench, north of New Zealand.

Using a large metal trap outfitted with cameras, they’d hoped to haul up a species of deep-sea snailfish that had not been captured in more than 60 years. Instead they hauled up, from nearly 33,000 feet below, seven milky-white amphipods measuring to about 11 inches, or the size of small lobsters. (Ordinary amphipods barely exceed 1 inch.)

Dr. Alan Jamieson, from the University of Aberdeen’s Oceanlab, said on the facility’s website, “The moment the traps came on deck we were elated at the sight of the snailfish as we have been after these fish for years. However, seconds later, I stopped and thought, ‘What on earth is that?’ It’s a bit like finding a foot-long cockroach.

The mysterious find was not totally unprecedented. The term ‘supergiant’ was used by American scientists who hauled up unusually large amphipods off Hawaii in the 1980s.

Jamieson added: “The surprising thing is that we have already been to this deep trench twice and had never come across these animals before. In fact a few days after the discovery we deployed all the equipment again on the same site and we didn’t photograph or capture a single supergiant; they were there for a day and gone the next.”

While they only caught seven of the enormous amphipods, they saw several others, including some that measured about 13 inches.

The seven specimens were being kept in Wellington, New Zealand, until the expedition is concluded.

– Image showing “supergiant” amphipods is courtesy of the University of Aberdeen’s Oceanlab