Amulet of return

This amulet allows you to keep one large sized or smaller beast or monstrosity that is friendly to you in a safe, habitable demi-plane. While stored within the amulet the creature requires no food or water and does not require sleep. You can summon the beast as a bonus action to an unoccupied space within 5ft of you and return it to the amulet as a bonus action. 

Notes: Short rest