|Species:||Terran House Cat|
Data chose to have a pet as part of his efforts to become more Human and despite not having emotions until 2371 Data always had a great deal of affection for her, developing no less than 221 different feline supplements to satisfy Spot's dietary requirements (TNG episode: "Data's Day").
Spot exhibits a similar amount of attachment to Data but is less fond of the rest of the USS Enterprise-D's crew, after having being cared for by quite a variety of Data's friends. William T. Riker once agreed to take care of Spot, which ended abruptly when Spot scratched him. After treating the deep scratches that Spot gave Riker, Beverly Crusher then agreed to take care of the cat, and Commander Riker suggested that she take a phaser along. When Geordi La Forge took Spot in briefly to see what having a cat would be like, Spot wrecked his quarters before hiding under La Forge's bed. Worf once agreed to take care of Spot, but found himself to be allergic to cats and sneezed on Spot. The only other person Spot really seemed to get along with was Reginald Barclay (who later got a Cat of his own). (TNG episodes: "Timescape", "Force of Nature", and "Genesis").
In 2370, Spot became pregnant, sired by any one of the Enterprise's twelve male cats and eventually gave birth to five kittens. During the last days of her pregnancy, a synthetic T cell was causing the crew of the Enterprise to de-evolve. Spot was also affected, and was transformed into a lizard just as she was giving birth to her kittens. The kittens were not affected by the disease, and when discovered by Captain Jean-Luc Picard and Data, the pair realized that they had a potential method of reversing the effects of the T-cell virus. Data was able to use amniotic fluid from the pregnant Alyssa Ogawa to create a retrovirus to eliminate the T-cell virus and return the crew to normal, including Spot. (TNG episode: "Genesis")
Following Data's death, ownership of Spot fell to Commander Worf, who had recently returned to the Enterprise. Spot and Worf did not get along at first, but Worf soon came to see the feline as a proud warrior who sees what she wants and takes it. (TNG - A Time To... novel: A Time for War, A Time for Peace; TTN novel: Orion's Hounds)
In 2384, upon Data's return, Spot stayed with Worf as Data didn't feel obligated to rejoin Starfleet due to the fact his father disliked the idea. By this year, Spot was seventeen years old and was expected to live another decade. (TNG - Cold Equations novel: The Persistence of Memory)
Spot was a subject during Data's experiments with producing paintings, including a large canvas with a stylized image of Spot that Data displayed in his ready room during his command of the USS Enterprise-E. (ST - Countdown comic: "Countdown, Number Two")