Three-headed Collar

Wondrous item, uncommon (requires attunement)

Price: 450-800 gp | low sentimentality

There are three collars connected to a leash. The collars only fasten around beasts with an Intelligence of 6 or lower. The distance between the collars and the length of the leash magically change to accommodate the size of collared beasts. One collar holds one beast unless the beast has more than one head. Collared beasts share senses and act as one creature, though they retain their individual abilities and actions. In combat, they share the same initiative order.

To collar a beast, you must grapple it while holding the collar.

Paid

While you hold the leash, collared beasts don’t attempt to escape from you. The collar makes collared beasts non-hostile toward you but doesn’t compel them to be friendly or obedient.

Overpaid

You have advantage on skill checks to fasten the collar around a beast.

Source: The Gray Merchant of Asphodel