Dr. Killington was a human doctor who operated on Chazz when his appendix nearly burst. Carmen didn't initially trust him, and was soon joined by Poncho after he discovered that the doctor was a cat person. In an attempt to calm Poncho and Carmen, he revealed that other children made fun of hislarge head when he was a child. This caused him to become socially alienated and vengeful, and perform horrible experiments on his stuffed animals.