A team of divers set off to explore a sunken World War II ship off the Norwegian coast, but what they found was something far more mysterious. While making their way back to shore, Ronald Raasch, Nils Baadness and Brynjar Aarnseth came face-to-face with a giant floating orb.

The bubble hovered 17 meters (56 feet) below the surface and appeared to be see-through. The divers turned their flashlights on it and realized that the sphere was filled with hundreds of thousands of little animals. © Caters “At first I thought it was a giant jellyfish, but when we came a bit closer, we saw that this was [like] nothing else we had seen before,” Baadness told The Dodo. “It was amazing.”

Baadness recognized the sphere as a giant squid egg — something he had only seen on the news. “To see it in person was a once-in-a-lifetime moment,” Baadness said.

Ronald Raasch, who is part of the REV Ocean research team, filmed the divers' encounter with the otherworldly object and posted it to YouTube:

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The REV Ocean team has been researching these mysterious egg sacs, and have collected four samples from Norwegian waters so far this year.

"They were genetically tested, and turned out to match the 10-armed squid Illex coindetii (southern shortfin squid)," Halldis Ringvold, a researcher with Sea Snack Norway's Gelatinous Sphere Project, told The Dodo. "The jelly ball from the video ... has not been genetically tested, but is similar to the other jelly balls which have been tested."

The southern shortfin squid, found in the North Atlantic Ocean and the Mediterranean Sea, is between 8 and 16 inches long (not including their legs). They can somehow lay a giant sphere, around one meter (3 feet) in diameter, that's filled with eggs.

Not only was the divers' rare sighting a great thing for science — it was an experience they will never forget.

“We were very lucky to be there at the right place at the right time,” Baadness said. "We will probably not experience this ever again.”