There's something very fishy about this knife.
Rather, the entire thing is carved from a block of dried and smoked bonito tuna called Katsuobushi—a Japanese preparation that holds the Guinness World Record for the hardest food on earth.
When shaved into flakes, Katsuobushi imparts umami flavor into the dashi fish broth used to make miso soup.
As this YouTuber demonstrates, one can also craft a hunk of the stuff into a full-size blade.
It may not be as flashy as these pocket knives made from Woolly Mammoth tusks and dinosaur bones, but it's still pretty badass.