Keen Sight and Smell. The owlbear has advantage on Wisdom (Perception) checks that rely on sight or smell.

Stalker in Mist. The owlbear has advantage on stealth checks if it is within dim light, darkness, or is obscured in any way. If it is within the Shadowfell or mists of a dread realm, it may add its proficiency bonus twice to its stealth check. It also does not suffer disadvantage from obscured sight to mist or fog (or similar obscuring natural phenomena)

Ambush predator. The owlbear may make a Hide action as a bonus action.

Multiattack. The owlbear makes two attacks: one with its beak and one with its claws. It may choose to replace one of these attacks with a pellet attack if it wishes.

Beak. Melee Weapon Attack: +9 to hit, reach 5 ft., one creature. Hit: 10 (1d10 + 5) piercing damage.

Claws. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 14 (2d8 + 5) slashing damage.

Pellet Bomb (3 of Day). The shadow touched owlbear can vomit up a pellet of bones and negative energy. Hocking the thing at long range it can choose any creature or spot at 120ft or less, using its Wisdom instead of Dexterity for the rolls if it wishes. On hit the pellet explodes in a gory rain 20 ft in radius. All creatures within the radius take
(4d6 + 4) 4d6 points of piercing, 2d6 (2d6) points of acid, and 2d6 (2d6) points of necrotic damage or half of the total on a DC 18 Dexterity Saving Throw. The owlbear only regains use of this feature on the next day if it consumes something after using it.

Erie Shriek (Recharge 4-6). As a bonus action, the owlbear lets out a terrifying shriek. Any creature within 120 feet of the creature must make a DC 19 Wisdom Saving Throw or be frightened of the creature for 1 minute. The save may be repeated at the end of an effected creatures turn, on success they are immune to the frightened condition caused by this cry but not its next effect. A creature within 30 feet must also succeed on a DC 19 Constitution Saving Throw or be stunned until the beginning of the Owlbear's next turn.