It was the first time for Cirno and Wriggle to meet one of the mountain's Reimus.
Fearing that this hardly scary Koreimu would eat them, the two yukkuri escaped with all their power.
Right then, Cirno dropped its wings.
Though the wings are not needed while running, in times of need, the wings are formed by freezing the water vapour in the air to enable flight.
Simply put, with the hardened shape of the ice, there are times Cirno holds it in its mouth to dig holes.
"Wait up easy!! Wait up easy!!"
Though it can't catch up to the adult-sized Cirno and Wriggle, Koreimu gives chase desperately.
This is because it has an odd sense of responsibility to let the two uneasy yukkuris take it easy.
Not looking where it is jumping, Reimu doesn't notice Cirno's dropped wings, and lands on them.
"Yugyaaaaaa!! Reimu's feeeeet!!"
A piece of ice has sliced into Reimu's lower part.
Though it is light, it is a huge matter for a koyukkuri.
"No more!! Reimu's going home!!"
Writhing about in pain, it runs away.