Heikegani (平家蟹, ヘイケガニ, (Literal meaning: Heike Crab), Heikeopsis japonica) is a species of crab native to Japan, with a shell that bears a pattern resembling a human face - an example of the phenomenon of pareidolia - which is interpreted to be the face of an angry samurai, hence the nickname samurai crab. The crabs are named after the once powerful Taira clan which dominated medieval Japan, commonly known as the Heike. It is believed that these crabs are reincarnations of the Heike warriors defeated at the naval Battle of Dan-no-ura as told in The Tale of the Heike. While the crabs are edible, they are not eaten by most Japanese.

In Culture

In Kwaidan: Stories and Studies of Strange Things, the writer, Lafcadio Hearn, references the Heike crab in "The Story of Mimi-Nashi-Hoichi."

In the 1964 Japanese anthology film Kwaidan, based on Hearn's stories, "Hoichi the Earless" recounts the story of the Battle of Dan-no-ura, which becomes the basis of "Hoichi the Earless." The narrator explains the myth, illustrated with prominent footage of the crabs. At the end of the "Hoichi the Earless" segment, Hoichi is seen playing the lute, with heikegani on his shoulders.

In his 1980 science series Cosmos: A Personal Voyage, Carl Sagan used heikegani to illustrate artificial selection. British biologist Richard Dawkins discussed the same idea in his 2009 book The Greatest Show on Earth: The Evidence for Evolution.

Heike crabs appear as an important part of the plot in one of the comic book stories of Usagi Yojimbo, a rabbit samurai character created by Stan Sakai. The "Grass cutter" story published in volume 2 of the Usagi saga tells the legend of how a sacred sword kusanagi was lost and then found with help from samurai crabs.