Tac-Nine, also known as Tac-Neuf or T-9, is a cyborg cat. She is the sister of Tac Nayn. She is younger and smarter than her brother. She is a black furred cat that has been infused with a computer. She has a green and black rainbow trail with a trail of binary digits. She is so powerful, that she could kill Nyan Cat. She lives in a small cottage with her brother. She has been kept in a cage before because she is so dangerous. She likes to eat anything she finds (including other cats). She has no friends. She is also, like her brother rumored to be responsible for Violet's (Mrs. Nyan Cat's) death. Her infamous quote is "If my brother can't destroy the planet Earth, I WILL!"

She is not really known and doesn't even have her own video. Also, no other information about her cannot be found online, so it may be possible that this is still only newborn fanon or it could be fake.