According to japanese folklore, kanibōzu are giant crabs which disguise themselves as priests and haunt temples. Kanibōzu move into old, empty temples which have no head priest maintaining them. From there, they harass people living in the vicinity. When a traveling priest visits such a temple, or when a new priest is dispatched to lead such a temple, the kanibōzu appears before them and demands they answer a riddle. If the priest cannot answer correctly, they are eaten.

Several temples are home to kanibōzu legends, including Chōgenji in Yamanashi Prefecture, Yōzenji in Ishikawa Prefecture, Hon’eiji in Toyama Prefecture, and Kanpōji (destroyed in 1750) in Iwate Prefecture. The tales vary from place to place, but they usually tell of a kanibōzu who commits evil deeds until it is defeated by a priest — sometimes after a battle. At Chōgenji there is even a stone which is said to bear the scars of the kanibōzu’s claw marks.

The legend of a riddle-giving crab was popularized in the kyōgen play “Kani yamabushi”, which helped to spread this legend across Japan.

Long ago, there was a temple in which priests kept disappearing one after another. Every time a new head priest was dispatched to the temple, they disappeared after one night. Soon, the villagers began to think the temple was haunted. No new priests were willing to go to there, and it fell into ruin.

Then one evening, a wandering priest came to the village. He went from door to door looking for a place to rest, but every one told him to go to the old temple. Completely unaware of the danger, the priest did as he was told and upon arriving at the temple, weary from travel, he fell fast asleep.

The traveling priest awoke from his dream to a strange sound nearby. Looking up, he saw another priest standing next to his bedside. The priest glared fiercely at him and asked a riddle: “What has eight small legs, two large legs, walks sideways, and has eyes pointing straight towards heaven?”

The traveling priest thought for a moment, and then replied, “You are a crab!” Then he quickly struck at the strange priest with his staff. Startled by the sudden attack, the strange priest shed his disguise and became a gigantic crab. It scuttled sideways out of the temple. The traveling priest threw his staff at the crab, cracking its shell, but it managed to escape.

In the morning, the villagers came to the temple to see if the traveling priest was still alive. The priest told them to drain the pond behind the temple, for a yōkai lived inside of it. When the water was drained, they discovered the body of the enormous crab with its shell cracked open. They also discovered the skeletons of all the priests who went missing from the temple.

After that, the traveling priest became the new head priest of the temple. And nothing strange ever happened there again.