Hallow’s Cat

Wondrous item, uncommon (requires attunement)
  In each of the many bedrooms of Hallow’s Inn is a stuffed toy. One of these toys, a skinny black cat with large, bat-like membranous wings, made it out of the Inn in Heliana’s satchel of looting. Only when playing with it later did she realise the truly mischievous nature of this would-be kid’s toy.
  Find Familiar. If you use an action to tickle the stuffed toy’s belly, the cat immediately becomes flesh and bone, whereupon it sinks its claws into your hand, dealing 1 slashing damage to you. The cat becomes your familiar as per the find familiar spell for the next 8 hours. Hallow’s cat has the statistics of a cat with 15 hit points, a flying speed of 50 feet, the construct type instead of beast, immunity to necrotic and poison damage, and immunity to the charmed and frightened conditions. At the end of the 8 hours, or if Hallow’s cat is reduced to 0 hit points, it turns back into a (slightly more ragged) stuffed toy and can’t be activated as a familiar again until the next dawn.