They live in a derelict gas station in the middle of the desert. Despite their scary appearance, they are quite friendly and hospitable.
The scary old family are two deformed humanoids. Their skin is pale blue, and have black and yellow eyes. The scary old man is bulky, with long arms, and only has one tooth in his mouth (which falls out early in "The Vacation," making him toothless). His mother is short and skinny, and sits in a wheelchair.