[Demonskid]

erm if I remember they are spirits of cats. lemme find the wiki

Bakeneko (化け猫?, "monster-cat"), in Japanese folklore, refers to cat yōkai (spiritual beings) with supernatural abilities akin to those of the kitsune (fox) or tanuki (racoon dog). There are a number of superstitions that detail how ordinary cat may transform into a bakeneko. Bakeneko then haunt and menace their household.

A bakeneko with a forked tail is referred to as a nekomata (猫又?, or 猫股 "forked-cat"). The popular good luck totem, the Maneki Neko (招き猫?, "Beckoning Cat") found in shop fronts is also a type of bakeneko. [1]

Most of the stories about the bake-neko are told orally in Japan.

http://en.wikipedia.org/wiki/Bakeneko
more info go to the wiki ouo