This mushi has two names, Yado-karidori (hermit reaper - apparently this is a pun), Sezuri-kai (chirping shell). This is a type of mushi that looks a great deal like a small bird.
[Sezuri-kai flying.]
They live flying over the ocean, eating various oceanic detritus like dead seaweed. However, if some sort of disaster threatens the ocean, they come ashore and hide in abandoned shells until the disaster passes. There is no way to know for sure what sort of disaster it could be. The mushi hide from disasters ranging from a red tide, to an exceptionally high tide, to a big storm.
[Sezuri-kai hiding in a shell.]
While hiding, they constantly chirp to warn others of their kind about the danger; if a human puts one of these chirping shells up to their ear, they forget how to talk. Thankfully it's temporary; one only needs to listen to other humans speak and they will eventually recover their voice on their own.
Sezuri-kai/Yado-karidori
[Sezuri-kai flying.]
They live flying over the ocean, eating various oceanic detritus like dead seaweed. However, if some sort of disaster threatens the ocean, they come ashore and hide in abandoned shells until the disaster passes. There is no way to know for sure what sort of disaster it could be. The mushi hide from disasters ranging from a red tide, to an exceptionally high tide, to a big storm.
[Sezuri-kai hiding in a shell.]
While hiding, they constantly chirp to warn others of their kind about the danger; if a human puts one of these chirping shells up to their ear, they forget how to talk. Thankfully it's temporary; one only needs to listen to other humans speak and they will eventually recover their voice on their own.