Neighbor Bill was a neighbor of Rat and Pig's. He appeared in two strips, the second several years after the first, with a drastically changed design.
In his first appearance, Pig explained to Goat that Bill had to meow and bark for his dog and cat, as each had laryngitis. At this time, he looked much like Neighbor Bob's most common appearance, bald and fat.[1]
In his second appearance, Bill called on Rat to ask why the two hadn't spoken in a while. Rat replied that Bill was an "Olympic Neighbor"; someone you only need to see one every four years. His appearance then was the same body shape, but he also had glasses and black hair.
In Bill's last appearance, he is seen as elderly with grey sideburns, in this strip he is skinny and exercises constantly, he don't drink, smoke or eat unhealthy to low his chance of a heart disease, while explaining how he does it to Rat and Pig he suddenly has a heart attack, which killed him.