Familiar

Familiars are magical creatures introduced in The Sims 2: Apartment Life that required The Sims 2: Pets, and were reintroduced in The Sims 4: Realm of Magic.

The Sims 2: Apartment Life
If players also have Pets installed. Witches can summon their own Cat Familiar called the Spectral Cat.

The Sims 4: Realm of Magic
In Realm of Magic. Spellcasters can acquire magical familiars that can aid in spell duelling. If players own Cats & Dogs; they can make their pets familiars as well.