Billy Moon is a character on Frasier.
Billy is one of Daphne's many brothers and is the sole of the Moon sons not to work at the docks. He is matriarch Gertrude's favourite son and teaches ballroom dancing. Daphne mentions how Billy has never peeked on her while she was undressing or showering, as all the others did during their years of pubescence. Billy did peek on all the other brothers, though.