It was spotted by a scientist in a big freezer full of giant squid.
It was caught off the coast of New Zealand last October, is about four metres long and weighs about 12 stone!
It has been identified as a type of octopus that's normally found in the sea near Japan, not New Zealand.
Damaged in freezer
Unfortunately it's been a bit damaged since it has been in the freezer.
One scientist said it would have been even more impressive if it was whole.
"It would have looked like a huge jelly fish or a great, big, thick umbrella," he said.
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