Battle of Yashima, March 22, 1185 (colorized)

Battle of Yashima in Japan was one of the battles of the Genpei War between Minamoto clan and Taira clan during the Heian period.

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. (Wikipedia)

However, according to the latest research, Heike Crabs are actually descendants of Giant Enemy Crabs (Macrocheira gigas), which fought in the famous Battle of Yashima, as shown in this painting.

"When one faces a giant crab in his life, he must attack the weakest point on its body to cause it great injury and win the day." (Sun Tzu)