Forest Stalker. The Stalker Beast has advantage on Wisdom (Perception) checks while in a forest.

Mask of the Wild: The Stalker Beast can attempt to hide even when it is only lightly obscured by foliage, heavy rain, falling snow, mist, or other natural phenomena.

Sudden Strike. When the Stalker Beast attacks an enemy it has surprised, critical hits land on a 19 or a 20.

Pounce. As long as the Stalker Beast has more than half of it's base movement speed remaining, it can, instead of moving normally, make a Pounce action. By doing so, the monster makes a powerful leap towards a singular prey. There cannot be any obstacles higher or lower-hanging than 5 feet in the way of the Pounce, and a Stalker Beast cannot move more than 30 feet at once with one Pounce. Any creature who is now 5 feet away from the Stalker Beast takes a number of points of Bludgeoning Damage equal to the amount of intervals of 5 feet the Stalker Beast travelled using the Pounce times two and must make a DC 15 Dexterity (Acrobatics) check or be knocked prone, and must remain prone until no longer in combat range of the Stalker Beast. A Stalker Beast cannot perform another Pounce for two rounds after making a Pounce action. A Pounce action counts as Movement, and the Stalker Beast can make a main action afterwards as normal (eg, attack).

Flammable Hide: The Stalker Beast's hide is thick and shaggy, and highly susceptible to fire. Whenever this monster takes Fire damage or enters a space with a similar effect (eg, an area with the Create Bonfire spell cast on it), it is set on fire. The Stalker Beast becomes Frightened as long as the flame is active and takes 5 (2d4) Fire Damage on every turn it starts on fire. The Stalker Beast will first try and attack the creature that set it aflame, but once it's hit point total goes below 19, it will turn and flee. If a source of water is nearby, it will always go towards it first to stop the flames.

Multiattack. The Stalker Beast makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 14 (2d8 + 5) piercing damage.

Claws. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 12 (2d6 + 5) slashing damage.

Frightened Retreat. If the Stalker Beast is set on fire (see Flammable Hide), it can move up to half of it's current movement speed away from the source of the attack.