Mordecai and the Rigbys

Synopsis
When Mordecai and Rigby order T-shirts for their non-existent band (Mordecai and the Rigbys), Margaret mistakes them for actual musicians. Mordecai, who wishes to impress Margaret, decides to go along with this misunderstanding by forming a real "Mordecai and the Rigbys" band. However, neither Mordecai nor Rigby have any idea how to play music. Later, Mordecai and Rigby's future selves (who became successful musicians) arrive. Future Mordecai and Future Rigby teach their present selves how to become musicians, but soon conflict is ignited when Present Mordecai and Present Rigby learn that they were duped into lip-syncing.

Plot
Mordecai and Rigby order a box of fake band t-shirts after the night pictured, which leads to Mordecai convincing Margaret that the band is real the next day. The band is called Mordecai and the Rigbys. The band name was going to be Mustache Cashstash but Rigby changed it at the last minute. Margaret hands them a flier for the open-mic night at the coffee shop where she works and tells the two they should play at it. Wanting to impress Margaret and so she doesn't think they have a "stupid fake band", Mordecai tells her that he and Rigby will play at the show. Realizing that they don’t know how to play, Mordecai and Rigby go to Pops for help, only to learn that he and everyone else from the park are also going to be attending the open-mic night. Pops gives Mordecai and Rigby three records to help them learn to play in time, but they are extremely dated, and less than helpful.

To speed things up, Mordecai and Rigby try playing all three records at once. When a drink is spilled, however, this causes the record players to react with one another, resulting in Mordecai and Rigby’s future selves to appear (where it turns out they are both very successful musicians). The future selves teach Mordecai and Rigby the lyrics, the moves, and the looks, but never how to play.Future Mordecai and Rigby hand them both guitar picks and tell them that they will be great, though. Sure enough, when they get on stage, they perform amazingly, impressing even Benson. Halfway through the performance, though, Mordecai realizes that their equipment is not plugged in, and their performance is being played from a tape. He stops Rigby and the performance, and gives a talk about how lip-syncing is 'not cool', and then rips his shirt in two. This causes the future selves to disappear forever. Unfortunately, though Margaret is still impressed with Mordecai, she asks if he has met her new boyfriend, Angel, one of the earlier performers who mostly sings instead of talking. After this, Rigby tells Mordecai maybe he should have kept lip-syncing.