Mimic Ship in a Bottle

Wondrous item, uncommon
  Each time this ship-in-a-bottle is observed, something is slightly different. One time it might have three masts. Another time, the figurehead might have changed from dragon to narwhal, or the rigging has become a light shade of mauve. The only constants are the cannons, its malevolent ‘grin’, and the tentacles. This ship is, in fact, a baby mimic, that hasn’t quite mastered the art of ‘mimicking’.
  As an action, you can uncork and upend the bottle, casting the spell find familiar requiring no material components. The familiar takes the statistics of the ship mimic offspring* and is friendly to you and your companions. If the mimic is killed, a new mimic appears 8 hours after you fill the bottle with water and salt.