Keen Smell. The cat has advantage on Wisdom Perception checks that rely on smell.

Amorphous. The shadow can move through a space as narrow as 1 inch wide without squeezing.

Sunlight Weakness. While in bright light created by sunlight, the shadow cat has disadvantage on attack rolls, ability checks, and saving throws.

Truesight. A monster with truesight can, out to a specific range, see in normal and magical darkness, see invisible creatures and objects, automatically detect visual illusions and succeed on saving throws against them, and perceive the original form of a shapechanger or a creature that is transformed by magic. Furthermore, the monster can see into the Ethereal Plane within the same range.

Familiar. The Yule Cat can serve another creature as a familiar, forming a magic, telepathic bond with that willing companion. While the two are bonded, the companion can sense what the Yule Cat senses as long as they are within 1 mile of each other. While the Yule Cat is within 10 feet of its companion, the companion shares the Yule Cat's Magic Resistance trait. At any time and for any reason, the Yule Cat can end its service as a familiar, ending the telepathic bond.

Claws. Melee Weapon Attack: +0 to hit, reach 5 ft., one target. Hit: 1 slashing damage.

Shadow Blend. While in dim light or darkness, the shadow cat can use a bonus action to become invisible, along with anything it is wearing or carrying. The invisibility lasts until the shadow cat uses a bonus action to end it or until the shadow cat attacks, is in bright light, or is incapacitated.

Shadow Stealth. While in dim light or darkness, the shadow can take the Hide action as a bonus action.