From The Heretic Knowledge Vault
He and housemates Marx and Zakmar are classic aliens -- well, semi-classic -- with bald heads, large black eyes, the whole shtick. They live in a house in the same neighborhood as Fran, Naga, Seth, Nikki, and so on. Their move into this house, displacing the Franklin family, occurs during the night, can reasonably be described as "sudden," and annoys Naga with the noise. She doesn't seem to mind the flying saucer at all, however.
They're all regulars at the role-playing games that have been a recurring DNPWWO plot device. The game is part of the reason why they all got exiled from their home planet, but another factor is that Bill has "gone native," including discovery of certain hydroponically-grown Earth plants that he finds ... interesting.