Spectral cat
A spectral cat is a cat that can be summoned by a witch through the spell "Apello Cattus Amicus." Players need Apartment Life and Pets to do this task.
The first time the familiar is summoned the player will be told to give it a name. This shining, ghost-like cat will be a witch's companion and familiar, and will have some new features that normal cats don't have.
The spectral cat will never age, has no gender and is unable to breed. It also doesn't have the bladder need, so litter boxes are unnecessary. If one of its need bars ever gets too low, or if the summoner witch leaves the lot, it will vanish, and can be summoned with the same spell with its needs full.
Unfortunately, no spectral cats can have a career. The cat's appearance will reflect the witch's alignment: white cats with blue aura for good witches, dark grey cats with orange aura for neutral witches and black cats with green aura for evil witches.
Moving Out
If the witch moves to another lot without the spectral cat with her then the next time the cat is summoned, a new cat will appear and the player will have to name the cat again. In order to prevent this, before moving the entire family out, spectral cats must be summoned and present, and then go to the Neighborhood view. After that, you can safely move in the family with the same spectral cats.
So the conclusion is, spectral cats must be present whenever a witch wants to move out, even if they want to find own place.