The jaw of a hyena with boons granted by the demon lord Yeenogu himself. The Grin's purpose is to sow destruction across the material plane in the hands of a mortal. A piece of the demon lord's conscious rests within the Grin making the item sentient. The Grin is a faded yellow looking like rotted teeth. When attuned to the Grin the user has a perpetual abnormally large grin on their face. The Grin can transmit its own feelings and emotions to the user and has hearing and dark vision out to 120 feet. It's alignment is chaotic evil.

Yeenogu’s Boons:While attuned to the grin the user has +2 to Strength and Dexterity and -2 to Intelligence and Charisma. The Grin has 6 charges and regains 1D4+1 charges at dawn daily. The following spells can be cast using an action; Tasha's Hideous Laughter (1 Charge), Crown of Madness (2 Charges), and Fear (3 Charges). The spell save DC is 12.

Bloodlust: Whoever is attuned to the Grin can use an action to make the Gnashing Jaws melee attack. It has a reach of 5 feet and has a bonus of proficiency plus the attuned's strength mod. It does 1D4 piercing plus proficiency and strength.  The attuned also has the rampage trait, when they reduce a creature to 0 HP with a melee attack or spell on its turn, it can take a bonus action to move up to half its movement speed and make the gnashing jaws attack once.

The Grin has the following minor and major benefits and detriments:

Minor Benefits: Proficiency in religion and immunity to disease.

Minor Detriments: Attuned must eat and drink six times the normal amount per day and non magical flames in thirty feet are extinguished.

Major Detriment: Potions within ten feet rendered inert

Major Benefit: Regain 1D6 HP at the start of each turn if the attuned has at least 1 HP

Notes: Bonus: Dexterity Score, Bonus: Strength Score, Bonus: Charisma Score, Bonus: Intelligence Score, Proficiency: Religion, Immunity: Disease, person who has shook hands with the hyena guarding the Grin, after attuning the user's jaw is violently ripped from their face as the Grin takes it place.