The "witch" in its refers to Immorticia. The word "familiar," in this case, means a demon supposedly attending or obeying a witch, often said to assume the form of an animal, referring to the Zom-Bats it makes. Its name could also be a pun on the question "Which is familiar?". It may also be an allusion to the title of a Doctor Who episode "Witch's Familiar."
Its ability is a reference to how witches are commonly associated with bats.
Its flavor text is based on the saying 'bats in the belfry.'
Statistics
Classes: Brainy, Beastly
Tribes: Pet Superpower Trick
Ability: Make .
Set - Rarity: Premium - Legendary
Card description
Immorticia was cleaning her belfry when, lo and behold, she found bats in there.
Update history
Update 1.24.6
▲ Can now be played on aquatic lanes.
Strategies
With
Witch's Familiar is best compared to Neptuna's signature superpower, Octo-Pult. Whereas Octo-Pult is best used to attack the Plant Hero directly, Witch's Familiar is meant to front plants, specifically those have high health but no strength, such as Wall-Nut or Torchwood. At worst, it'll block a threat and draw a card if Zom-Bats successfully damage a plant and at best it can be boosted to increase its longevity.
Since both Witch's Familiar and Zom-Bats are pets, it can boost zombies like Cat Lady and Zookeeper twice. As it's also a trick, it can activate Mad Chemist/Trick-or-Treater's abilities.
Against
Witch's Familiar can easily block a plant, give your opponent a minor card advantage, and that's not to mention its use in pet decks. Being a superpower, it may be difficult to predict when and where your opponent would play it. Nevertheless, it's best to destroy Zom-Bats as soon as possible before your opponent could potentially boost them.
Brainy and 
Beastly classes. It costs 1
to play, and its ability makes Zom-Bats on a selected lane. Its closest plant counterpart is Tater Toss.
.
Witch's Familiar's statistics
Witch's Familiar's card
Witch's Familiar's HD card
Immorticia using Witch's Familiar
Witch's Familiar being played
Witch's Familiar being played (animated)
Textures of Witch's Familiar card
Witch's Familiar's card image
Two Witch's Familiar cards in Super Brainz's hand, gained via two Thinking Caps
Witch's Familiar costing 0 brains
.png)
Witch's Familiar's statistics
Witch's Familiar's statistics
Witch's Familiar's statistics
Immorticia using Witch's Familiar
Zom-Bats' statistics
Sneaky class.
Brainy
Crazy
Hearty
Sneaky