Amulet of the Wolf (Slumbering)

This amulet is in the shape of a Wolfs head. Encrusted with jewels and made of intricately woven together silver, it has an empty chamber inside. To attune to the amulet, a creature must have more than one form or be granted natural weapons by class or race. A creatures racial weapon, such as Tabaxi claws, that do not specify it is a natural weapon but can be used for unarmed strikes, counts as a natural weapon for the amulet. 

Slumbering (Uncommon). You have advantage on Wisdom(Perception) checks that rely on hearing or smell. Additionally, Whenever you roll a 20 on your attack roll with your natural weapons, the creature is knocked prone.

Attunement: To attune to this amulet, you must be a creature with natural weapons or a racial feature that grants unarmed strikes.

Notes: Advantage: Perception, creature that has more than one form or that is granted natural weapons by class or race. Racial unarmed strikes (such as Tabaxi Claws) count as a natural weapon