A nasty and viscous Japanese house demon. They create ghostly fireballs, menace family members as they sleep and will even devour the mistress of the house so it can shapeshift and take her place given half the chance. They can also bring corpses back to life just by jumping over them.
Any old household cat can become a Bakeneko if it is allowed to reach a certain age, grow a long tail or reach a certain size. (From Gods Laid Bare)