Babbling Slither Horn

Pack Tactics. The Babbling Slither Horn has advantage on an attack roll against a creature if at least one of the baboon's allies is within 10 feet of the creature and the ally isn't incapacitated. 

Magical Resistance. The Babbling Slither Horn has advantage on all saving throws against spells and other magical effects. 

Maddening Babble. Upon falling below 20% of its maximum hit points, the Babbling Slither Horn lets out a cacophony of noises, resembling the distressed screeches of multiple different animals. All creatures within 100ft that can hear it must succeed on a DC16 Wisdom saving throw or gain the stunned status condition until the Babbling Slither Horn finishes screeching. The Babbling Slither Horn will only stop screeching if its health is restored to above 20% of its maximum, or it is incapacitated, or silenced by any other means (subject to DM's discretion).

Horned Strike. The Babbling Slither Horn drives its tough horns into a target. Deals 1d8 piercing damage.

Enraged Charge. The Babbling Slither Horn poises its body and charges forward by a maximum 30ft, dealing 2d8 piercing damage. On a hit, a target must succeed on a DC12 Strength saving throw or be knocked prone. This can be only used if the target is over 15ft away.

Claw Swipe. The Babbling Slither Horn strikes out at an enemy with its sharp claws, dealing 1d6 slashing damage. 

Coiling Crush. The Babbling Slither Horn wraps its serpentine tail around a target, attempting to constrain it. The target must succeed on a DC16 Dexterity saving throw or be grappled. The grappled target takes 1d8 bludgeoning damage for every turn it remains grappled. To escape, the target must succeed on a DC12 Dexterity or Strength saving throw. The Babbling Slither Horn can continue to attack with its claws while grappling a target. Once a target has broken free or died, this attack cannot be used again for 6 turns.