Grappler. The mist stalker has advantage on attack rolls against any creature grappled by it.
Mimicry. The mist stalker can mimic any sounds it has heard, including voices. A creature that hears the sounds can tell they are imitations with a successful DC 12 Wisdom (Insight) check.
Mask of the Wild. The mist stalker can attempt to hide even when he is only lightly obscured by foliage, heavy rain, falling snow, mist, and other natural phenomena.
Unarmed Strike. Melee Weapon Attack: +5 to hit, reach 10 ft., one target. Hit: 5 (1d4 + 3). If the target is a Large or smaller creature, it is grappled (escape DC 15). Until this grapple ends, the target is restrained, and the mist stalker can't grapple another target . If this attack is a critical hit, the target also can't breathe or speak until the grapple ends.
The thing in the mist. Barovia and the the domain of dread in general hid many dangers, with out a vistani guide the mist it self can quickly become even the bravest adventures end. many talk about the monsters and figures they see in the mist. Tricks the minds of adventures plays on them, but this is not always true. Some times the monsters they see are very real.
The lands surrounded by the mist sometimes tell tales of people that followed the crying of a child or a plea for help into the mist the ones that stayed behind reports of a long silence followed by the sound of bone gnawed off.
Looking like a starving human with gray skin this eyeless monstrosity tends to mimic voices to lure potential pray to it. It gaps it pray and dregs it into the mist. They try to strangle the victims to death but use the mist itself most of the time to finish them off.
In cold misty nights the sometimes venture out into the villages to hunt there and drag the pray they strangle back to the misty borders to consume them in peace.
According to folklore the first mist stalker was bone of a pregnant women that was lured into the mist only to find here end there, fearing for here child she made a pack with some malevolent force to make sure here child would survive. The souls child of her became the first mist stalker. It is said they reproduce be devoiding pregnant women to birth a new mist stalker.
Mist stalkers are able to live with in the mists that border the domain of dread but are unable to leave to due to there soulless nature.