Yadokaridori (ヤドカリドリ, Yadokaridori?, lit. Hermit crab bird), also known as Saezurigai (サエズリガイ, Saezurigai?, lit. Chirping shell, warbling shell), is a mushi that closely resembles a small bird. Its body is ivory-colored, and it has a white beak and a smooth white tail that curls down, similar to a seahorse's.
Yadokaridori are usually found out at sea, where they feed off of seaweed. When they sense disaster coming, they come ashore and burrow themselves in seashells and stay there until the danger passes. Their soft chirping can sometimes be heard coming from the shells, which is them calling their family to safety. If a human listens too closely to their song, they can lose their ability to speak. However, their speech can return by listening to other people talk, with better results the more voices and noises they hear.