Familiar Spirits were believed to help witches with their magic. It was believed that they were demons who took either animal or human form, notably that of a cat, rat or toad. In folklore if the familiar spirit belonged to a witch or sorcerer then the entity was generally seen as malevolent and labelled a demon and if the spirit was attached to one of the “cunning folk” then it was largely seen as benevolent and more fairylike.
Now I’d like to say that this is all complete fantasy, and it is true that I haven’t ever met a frog prince, never mind a mystical toad, but cats, well, we all know that cats are magical. Teabag is agile and swift as lightning… but he’s no dainty fairy and though he can at times be diabolical, he’s not evil. He does come and go silent as the grave… unless he wants some gravy… so I’d have to say at best, he’s benign.
I expect it’s all part of the mysterious cat magic, that makes me feed him and brush him. In his enchanted world I’m the familiar spirit who aids him with his magical comings and goings and doings, and who’s to argue with that? He believes in 5 impossible things before breakfast and then goes out and does them, while I pour coffee on my cereal and leave the hairdryer in the fridge. As usual I suspect we humans have the whole state of affairs backwards.