When it comes to hunting giant Alaskan king crab, brothers Johnathan and Andy Hillstrand are some of the best — but giant legendary sea monsters? That's an entirely different story, and the subject of a new special airing on the Discovery Channel later this month called "Alaskan Monster Hunt."

The Hillstrands, featured on the hit reality series "Deadliest Catch" as captains of the boat "Time Bandit," will investigate the existence of Cadborosaurus (nicknamed "Caddy" by locals), a sea serpeant similar in form to the legendary Loch Ness monster. There have been more than 300 sightings over the past 200 years in various places along the Pacific Coast of North America. 

According to the site Cryptomundo — which discusses news and evidence surrounding elusive and rare animals (or cryptids) — Discovery bought footage of a supposed Cadborosaurus from a Washington State fishing boat captain in 2009. That exclusive video will reportedly air during this special and, according to leading cryptozoological investigator John Kirk is likely to shed further light on the existence of "Caddy."

"I can fairly confidently say that readers will find this footage fascinating, and I hope that the producers of the program the creatures will be seen in, will have used all their electronic tools to show clearly the remarkable animals that the Washington state boat skipper and his sons have captured," he said last year in a post on the site. "If these are whales, moose, otters or other known creatures then they are subtypes that no one has ever seen before."

The teaser Discovery has given us below doesn't show much more than the Hillstrands fooling around — but there is a slight grainy shot of something a la Loch Ness. The network also invited cryptozoologist Dr. Paul LeBlond of the University of British Columbia to tag along as a consultant. 

I don't think they found anything — otherwise Discovery would be making a much bigger splash with this episode than what's currently out there. Nevertheless, it should be fun to finally see some of that video and come to our own conclusions as to what mysterious creatures might be swimming the depths around Alaska. 

Check out a teaser for the show below. "Alaskan Monster Hunt" airs on July 19 at 10 p.m. on Discovery Channel.

Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.

'Deadliest Catch' captains hunt for sea monster
Brothers Johnathan and Andy Hillstrand star in Discovery's spin-off special, 'Alaskan Monster Hunt.'