In the original OAV, the girl we will come to know and love as Nuku-Nuku starts out as two separate entities. A stray tabby cat, and the brainless android NK1124, created by the genius inventor Natsume Kyuusaku. Kyuusaku, and his son, Ryuunosuke, are on the run from Mishima Heavy Industries, from whom Kyuusaku has stolen the android.
Kyuusaku and Ryu stop to get some KFC. Ryu gets out of the car to take a leak, and comes back with a small stray tabby cat under his jacket, who Ryu wants to keep as a pet. Kyuusaku is explaining to Ryu why that would not be a very good idea at the moment, when they hear gunfire from above. Kyusaku guns the motor, and they drive at breakneck speed, trying to avoid aerial pursuit from Mishima, in the form of Poison-1, an advanced military aircraft. They drive through a junkyard, and crash into a towering pile of unidentified junk. Poison-1 riddles the car with bullets, and then flies off.
Kyuusaku and Ryuunosuke manage to come out unscathed. The cat, sadly, is not so lucky. We see Ryu with tears running down his face, holding the cat's limp body out to his father. The last shot is of Kyuusaku with a thoughtful look on his face, and a shot of the android's lifeless body slumped in the back of the car.
In the next scene, we are met with an attractive, nubile 16 year old girl, with long, purple hair, and two pointed front teeth, crying out, "Good morning! It's morning! Wake up!". This is Nuku Nuku.