Alaska might be known for its terrestrial predators and forested peaks, but the rich waters off its Pacific coast are teeming with wildlife. Many of the species that wash up on these shores are rarely seen, and the most recent find is no different.

The supersized cephalopod washed up dead this week in Unalaska, the largest city of the Aleutian Islands. However, when photos of the creature started making the rounds online, it was initially misidentified as a Humboldt squid (or "red devil"). What you're looking at is actually a robust clubhook squid (Moroteuthis robusta), a little-known species that inhabits waters from California to Japan.

The ID was confirmed by Alaska Sea Grant marine advisory agent Melissa Deiman Good, who visited the carcass earlier this week.

"This particular squid was pinkish-red in color with a five-foot mantle, slightly smaller than their maximum size," she wrote on Facebook. 

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Image: Melissa Deiman Good/Facebook
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Good takes a tissue sample from the squid's mantle. Image: Melissa Deiman Good/Facebook

Because they spend their lives at depth – typically below 500 metres (1,640ft) – most of what we know about clubhook squid comes from examining dead specimens hauled up by trawlers. And we don't know much: for all our years of study, we've yet to establish how many of them are out there or how long they live. 

While the origins of some animal common names can be a little perplexing (we're looking at you, chicken turtle), the clubhook squid is not one of them. Its tentacular clubs – those bulbous suckerpads at the end of the two long tentacles – are lined with hooks. Ergo, clubhook squid.

Each pad has about 15 grapnels, which come in handy when securing slippery prey like jellyfish or fending off predators.

"They're fed upon by sperm whales and other toothed whales," says Good. "What a great find!"

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Image: Melissa Deiman Good/Facebook

Exactly what killed this individual remains a mystery, but interestingly, other specimens of this elusive squid species have washed up elsewhere on the coast. Some 3,000 miles south of Unalaska in Washington's Puget Sound, clubhooks have turned up sporadically over the years – a pattern that has long puzzled Seattle Aquarium marine biologist Dr Roland Anderson.

"Puget Sound is an estuary, a fjord carved by glaciers," he wrote in a 2002 blog post for The Cephalopod Page. "Major rivers enter the Sound, which contribute to lowered salinity. [And] most squid are sensitive to brackish water." 

The Sound is also warmer than offshore waters, which is generally the case in coastal shallows. It's possible that these animals simply die when currents push them too far inland and out of their comfort zone. 

As for the Unalaska specimen, it disappeared just two days after it was discovered. Good suspects that local foxes and eagles took advantage of the free calamari.

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Top header image: Melissa Deiman Good/Facebook