"Cool" is a song from the musical West Side Story. Leonard Bernstein composed the music and Stephen Sondheim wrote the lyrics.
In West Side Story, "Cool" is a well known song that is sung by Riff before the Rumble meeting. The Jets are itching to fight with the Sharks, but Riff tells them to wait for the rumble.
In the movie, the song is placed after the rumble where Riff dies. The Jets are saddened by Riff's death and want revenge. When Action and A-rab start fighting, a man throws an object at them and tells them to go home. Action loses it and threatens the man, forcing the Jets to bring him into a warehouse. Ice (Tucker Smith), a character created for the film who is now their leader, has had it. He tells them they will have to play it cool in order to get through this.
This song is known for its fugal treatment of a jazz figure, described by one writer as "possibly the most complex instrumental music heard on Broadway to date".
In 2011, actor Harry Shum Jr. performed the song, as his character Mike Chang from TV series Glee, in the third episode of season 3, "Asian F" (aired on October 4).
An episode of Animaniacs features a parody version as "Coo Bird" sung by Bobby of The Goodfeathers. The song is also parodied in the Flight of the Conchords episode The Tough Brets with the song "Stay Cool, Bret".
The Castle episode "Cool Boys" has Richard Castle and Detective Slaughter sing it to distract some criminals hold them at gunpoint.