Yobuko

In Japanese folklore the Yobuko (呼子) is a yōkai (a supernatural monster) thought to reside in the San'in region and the city of Tottori. It was believed to be the cause of echoing.

Mythology
The Yobuko was thought to live in the mountains, and whenever a traveler entered the mountains and raised their voice, it would mimic them and call back.

In the artwork of Shigeru Mizuki, the Yobuko is depicted as a young boy with one leg, a large face, and wearing a straw rain hat. In the Oki Islands he was called Yobukodori (呼子鳥) and was said to be a bird.