The Kodama Mouse is a mountain anomaly told among Matagi hunters of northern Akita. It looks like a tiny, round-bodied mouse—somewhere between a house mouse and a dormouse. When it meets a person, it stops, swells rapidly, and is said to burst with a gun-like boom, scattering flesh—though some accounts say it only makes a deafening blast without bursting. The encounter was read as a sign of the mountain god’s anger; hunters who saw it were to stop hunting and leave the mountain at once.