Mother of the gods, the One, the Only, Mistress of the crowns, thou rulest all; Sekhmet is thy name when thou art wrathful, Bast, beloved, when thy people call. Daughter of the Sun, with flame and fury flashing from the prow upon the foe; safely sails the boat with thy protection passing scatheless where thy fires glow. Daughter of the Sun, the burial chamber lies in the darkness till thy light appears. From thy Throne of Silence send us comfort, Bast, beloved, banish all our fears... Mother of the gods, the great, the loved one, winged and mighty, unto thee we call, naming thee the Comforter, the Ruler: Bast, beloved, Mother of us all.
--The Book of Going Forth by Day, ca. 1550 B.C.E.
Bast, Sam & Steph Braithwaite, 2014 for Hero's Journey
Bast (or in the New Kingdom, Bastet) is the ancient Egyptian goddess of cats, an interesting thing to be goddess of when most Egyptian deities are in charge of natural features like "all of the sky" or "the entire Nile" or more aligned with social and political concepts such as kingship and technology. She does have other associations, notably the moon as well as protecting children and pregnant parents and being associated with healing ointments, but cats are really her major area of focus. Bast is an odd deity out, but her history helps explain that, because she certainly didn't start as a goddess of cats.
Originally, Bast was the Eye of Ra, which you might remember from the similar yet far more terrifying goddes Sekhmet, who is also the Eye of Ra. There are a lot of Eyes of Ra, in fact, what with him continually needing them to help him out but then their habit of inevitably going rogue and disappearing into the wilderness, and Bast is one of the most famous - so much so that late in the religion she was probably considered another face of Sekhmet, the gentle night to Sekhmet's blazing day. And like the other Eyes, Bast was originally depicted as a woman with a lioness' head rather than a cat's, and was thought of as a frightening, savage, but ultimately benevolent protector whose job was to serve and protect Ra and murder his enemies.
Just chillin' until some snakes need killin'
It isn't until about a thousand years into her worship that Bast starts to be shown as a cat instead of a lion, and no one is one hundred percent sure exactly why. There are a lot of theories: one is that there are enough lioness Eyes running around by this point to handle defending Ra and eating malcontents, Sekhmet being the most obvious example, and that Bast was so popular that her worshipers didn't want to lose her and instead adjusted her into being in charge of something else instead. Another is that this is around the time that Egypt began to have a lot of cultural commerce with Greece, and that Greeks identifying Bast with Artemis may have in turn influenced the Egyptians into considering her more aligned with the moon and the night, thus changing her nature.
Still another is that cats had simply become so big a deal to the ancient Egyptians that they needed a cat deity, and Bast was nominated due to being feline herself. While modern-day media depictions of ancient Egyptians as ridiculously devoted to and worshipful of cats are not accurate (they're still cats, after all - they still break your pots and poop in your shoes even when they're semi-divine), they were considered very important because of their ability to protect food stores by killing mice, rats, snakes, and other vermin, and were thought of as protectors of the home in much the same way Bast protected Ra, especially since they were capable of killing venomous snakes that otherwise could injure or kill members of the household.
The face of a deity who WILL steal your dinner if you turn around at the wrong moment
So Bast left her sisters in their lioness pride and became a cat. Cats are crepuscular and can see in the dark, so she became a goddess of the night and moon instead of the sun; cats are sneaky and silent, so she became associated with darkness and illusion; and cats are affectionate with humans and dote on their kittens, so she became associated with tender and loving motherhood and protection. And that's the Bast we have now, only egged on by the arrival of the Ptolemaic Greek-ruled dynasties later, which heavily leaned into the similarities to Artemis to move her even further from her feisty sun-warrior origins.
While we still have some fragmentary old stories about Bast wrecking Apep's face and fighting on the solar barque alongside the other gods, they had clearly fallen out of favor by later dynasties, probably because Sekhmet was right there still doing those things and just absorbed them. Bast's newer tales tend to highlight her mischievous, cat-like nature; one particularly popular one is that she once quarreled with her father Ra and ran away to live in the desert so that she didn't have to deal with him. However, while out there, she was stung by a scorpion (in some versions of the story, the scorpion-goddess Serket trying to get her to go home) and nearly died of the poison, forcing Ra to descend from the sky to heal her in spite of their disagreement. (Anyone who has ever had a cat who ate a wasp or the wrong kind of ant will probably find this a familiar tale of loving exasperation.)
Sacred to Pasht, Edwin Longesden Long, 1888
In Hero's Journey, Bast is very popular as a guardian of pets and children alike, and she chooses Heroes to grant similar powers to. All the Egyptian Heroes get to choose partners among their fellow Heroes to connect with and share power between; Bast's Heroes give their partners back Labors to use on incredible feats every time they use their own Labors on either the wily Trickster skills that Bast herself displays, or on Celestial powers associated with her heavenly domain (whether they prefer the classical moon or the more ancient sun).
It isn't hard to see why Bast is, has been, and probably always will be so popular: people love cats, and Bast makes sure they love us back. As a guardian of the weak and a pranker of the mighty, she embodies all the most loved qualities of felines; let she who defends the pharaoh and punks her priesthood be given all due reverence!