Keen Hearing and Smell. The Cat has advantage on Wisdom (Perception) checks that rely on hearing or smell.
Innate Spellcasting. The Cat's spellcasting ability is Charisma (spell save DC 12). It can innately cast the following spells, requiring no material components:
Constant: see invisibility
3/day: minor illusion
1/day: bestow curse
1/week: eternal rest
Magic Resistance. The Cat has advantage on saving throws against spells and other magical effects.
Black Coat. The cat's black coat of fur gives it advantage on stealth checks made to hide or travel in total darkness.
Multiattack. The cat makes two claw attacks.
Claws. Melee Weapon Attack: +5 to hit, reach 5ft., one target. Hit: 5 (1d4 + 3) slashing damage.
Bad Luck. A creature hit by the Cat's claws must succeed on a DC 13 Wisdom saving throw or be stricken with bad luck. For 1d4 rounds, the affected creature loses the ability to land critical hits (natural 20 rolls are treated as a normal attack roll) and also loses the ability to roll with advantage on attack rolls and skill checks.
Cuteness. The Cat behaves in a cute and adorable manner. This behavior often involves the Cat mimicking the common house cat's activities, such as playing with string, kneading with its paws, or rubbing against a humanoid's leg. Every humanoid within 60 feet that can see the Cat must succeed on a DC 12 Wisdom saving throw or be charmed until the Cat ceases its cute behavior. The cat must take a bonus action on each of its subsequent turns to continue behaving cutely. The effect ends if the cat is incapacitated. Any creature charmed by Cuteness is no longer charmed if it takes damage from the Cat. A target that successfully saves is immune to this Cat's cuteness for the next 24 hours.
Nine Lives. After death, this creature rises from the dead at the next sunrise at the den of the Cat-Sìth as if affected by a resurrection spell. This ability activates no more than eight times.
Description
Note: Some characteristics and part of the description are borrowed from the Wikipedia entry.
The Cat-Sìth (pronounced "Kü-Shee") is a fey creature resembling a black cat with a white spot on its chest. It is a stealthy protector of the forests of the Material Plane, as well as a resident of the Feywild. Few have seen the Cat-Sìth, but many rumors exist surrounding its existence and purpose.
Some say there is one, immortal Cat-Sìth, while others claim they are a race unto themselves. Some say they guard the hidden portals to the Feywild buried deep within jungles and forests in the Material Plane. Others have even reported seeing the Cat-Sìth steal the souls of the recently deceased.
In truth, the Cat-Sìth are a small collection of felines elevated to Fey by the gods of the Feywild. Their purpose is to stay out of sight or blend in, serving as a sort of reconnaissance unit of the Feywild. While they look nearly identical to one another, those without a sense of the Fey can identify them by the unique shape of the white fur on their chests, although few, if any, humanoids have come close enough to a Cat-Sìth to notice. They are gifted with several magic abilities, the strongest of which is power over death. Each Cat-Sìth is granted nine lives, lived out consecutively. And each has the ability to banish a dead creature's spirit to the afterlife, permanently, with the rest eternal spell.
While not directly serving the Fey gods, the Cat-Sìth are known to engage in mischief or other personal interests, especially those which play to their baser feline instincts.