She is a hairless cat that Mr. Crocker found in the episode, Viral Vidiots. He apparently found her up a tree and decided to name her "girlfriend" after she massaged his back with her paws. Despite Mr. Crocker's behaviour, she actually does seem to like being around him.
Girlfriend is a hairless cat with pink skin and purple eyes. The cat is quite skinny, with its skeleton being visible. It also has a red collar.
In her debut appearance, Girlfriend was a cat Mr. Crocker, who found her up a tree. She spent the episode with him while in the Crocker Cave, massaging his back and going with him on his plan to capture Mrs. Turner. Later on in the episode, Mr. Crocker asked her to attack Timmy, but she threw up a hairball instead. Mr. Crocker even notes how that doesn't seem to make sense since she has no hair to lick off in the first place. By the last scene in the episode revealed that Girlfriend was secretly recording the climax of the episode on a video camera to post on TooYube for viral fame.