Black Mist

shadow mist. when at night this beast become invisible only moonlight or lantern of revealing will show the beast location  (natural ability)

Alpha howl. when they howl they summon 4 shadow wolfs to its aid  (use stats for alpha wolf) only one uses.

Other worldly senses. the beast can sense players that are invisible or hiding and know where they are. (passive ability)

Multitrack. The beast makes two Claw attacks and one Bite attack

Claw Melee Attack. Melee Weapon Attack: +7 to hit, reach 5 ft., 1 target. Hit: 15 (3d6 + 6) [slashing] damage and if the target is a creature, it must succeed on a DC 21 Strength saving throw or be knocked prone

Bite Melee Attack. Melee Weapon Attack: +7 to hit, reach 5 ft., 1 target. Hit:  (3d8 + 6) [piercing] damage. If the target is a creature, it must succeed on a DC 18 Strength saving throw or be knocked prone.

Shimmer. black shimmer distorts on the body and vanishes the will reappear in an unoccupied space up to 60 feet and does not triggered attack of opportunity (can be use twice a day).

Bestial surge. the beast can use its aura to heal itself for 10d20. (can be use once per day)

Shadow Clone. can use the shadows to form copy of it self the copy will have max 100 hit points and can only use claw or bite attacks and can use shimmer 

opportunity of attack.

deadly stare. once hit as a reaction the beast can stare at the the target making a intimidation check of 20 (roll 1d20+str) on fail the target become frightened    

The beast can take 2 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature’s turn. The beast regains spent legendary actions at the start of its turn.

Frightful Howl (Costs 2 Actions). The beast howls as it blast its aura in a 120-foot cone. Any creature in that area must succeed on a DC 18 Wisdom saving throw or be frightened of the beast for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Paralyzing Stare. The target must make a wisdom saving throw of 19 or become paralyzed