"Careful with That Axe, Eugene" is an instrumental piece by the British rock band Pink Floyd. The studio recording, first released in 1968 as the B-side to the single "Point Me at the Sky" also featured on the 1971 compilation album Relics. Live versions can be found on various releases, the most well-known of which from the 1969 double-album Ummagumma. Pink Floyd re-recorded the track for the 1970 film Zabriskie Point, retitling it "Come In Number 51, Your Time Is Up" on the film's soundtrack album. The track was one of several to be considered for the band's 2001 "best of" album, Echoes: The Best of Pink Floyd, but it was ultimately omitted. Various versions, both live and studio recordings, were made available as part of the 2016 box set The Early Years 1965–1972.