Researchers recently discovered “supergiant” deep sea crustaceans that were more than 20 times larger than their crustacean relatives in an ocean trench off the northeast coast of New Zealand.

Scientists were dumbfounded when they found the giant shrimp-like creatures that measured about 11 inches long, and speculated that the rare species is closely related to the sandhopper or sand fleas, terrestrial species that are often washed up on the beach, but die quickly when they dry out.

“(After) the traps came on deck … I stopped and thought, ‘What on Earth is that?’ whilst catching a glimpse of an amphipod far bigger than I ever thought possible,” the expedition leader, Alan Jamieson of the University of Aberdeen's Oceanlab, said in a statement. “It’s a bit like finding a foot long cockroach.”

Researchers captured seven of these amphipods, and they said that these were the biggest whole specimens of supergiants recorded at nearly three times the size of what is considered a giant amphipod.

American scientists in the early 1980s coined the word “Supergiant” after catching a few large specimens off the Hawaiian Islands.

The supergiant amphipod (Alicella gigantean) was discovered in 1899 on a trawling expedition in the Atlantic Ocean. Another member of the species wasn’t seen until the 1970s when scientists photographed the enormous creatures in the northern Pacific near Hawaii.

Since then the supergiant has faded into the “realms of rare and mysterious deep sea creatures” researchers said.

Researchers made the capture down in the Kermadec Trench at about 4 miles below the surface, the deepest point that supergiants have even been found, according to researchers.

The scientists are now trying to determine whether the species they captured are the same as those seen decades ago around Hawaii.