He is a monster, he is Rokurokubi (ろくろ首 rokuro-kubi) is a Japanese youkai. During the day they have a human appearance, but during the night they gain the ability to stretch their necks, reaching a great height. They can also change their face to an oni face to scare away mortals more easily. Lafcádio Hearn makes a mistake in his book Kwaidan: Stories and Studies of Strange Things, and confuses these creatures with Nukekubi.