Well, new to us anyway, as the little monster recently adopted my wife and me.
Felis Catus (House Cat)
Hit Dice: 1-1
Armor Class: 4 
Attacks: 2 claws (1d2), 1 bite (1d4)
Saving Throw: 17
Special: Ambush, Gaze Attack
Alignment: Chaotic Adorable
Felis Catus is noticeably smaller than great predators such as the lion or the tiger. However, his tremendous speed and agility make him difficult to handle. Though low in hit dice, he is excellent at hiding under beds and couches and from such ambush positions he automatically surprises his quarry and obtains a +4 bonus to hit. A successful ambush attack does double damage against any normal target and quadruple damage against a human wearing socks. More dangerous than his ambush, however, is Felis Catus' gaze attack which acts as a charm person spell. Hapless humans suffer -4 to their saving throws against the gaze. Anyone failing the save must take the cat in, provide him with food and shelter, and regularly scratch him under the chin.