Rotten Rebecca is a character mentioned in ANDY HATES ROTTEN REBECCA!! (RAGE) and "WILLIAM AND ANDY BEAT EACH OTHER WITH THEIR PEPPERONI STICKS!!!".
While not stated, she is presumed to be Andy's psychotic ex-girlfriend. Little is known about her. However, she was mentioned and had tried to stalk Andy, and the judge said that Andy and her couldn't see each other. Little is known about her, but was revealed to have presumably dated and stalked Andy, making Violette go to court to testify. In one of their fan mail videos, they were asked about her, and William and Violette responded by saying they' will talk more about her in the future. In WILLIAM ANDY ANDY BEAT EACH OTHER WITH PEPPERONI STICKS!!!, she was briefly mentioned by William, who said Andy was probably saving his pepperoni stick for her.
Despite not being in a video, a lot of people hate her based on conclusions of her. They said that she is even worse than Bill as she likes to stalk Andy and getting herself in trouble with the law. However, some fans like the sense of mystery that she was added to the series, as not much is known about her. Those who are interested in finding out more about her often ask to know more details of her, which Violette said they might discuss in a future video. For now, she is mostly a mystery.