In the most recent build for Wrath Classic PTR, Build 47612, we’ve datamined some new models for a Rabbit companion and Rabbit mount. These will likely be part of some promotion related to the Chinese New Year and the Year of the Rabbit.
Edit – Hoplet (The Rabbit Companion Pet) is Available in game for players that have a 12-month subscription. Just speak to an innkeeper to complete the associated quest.