Never Gonna Give You Up was released by Rick Astley in 1987 and became a worldwide pop hit. Two decades later it became the centre of rickrolling, an internet bait-and-switch prank in which a disguised link promises one thing and plays Astley's song instead. The joke spread through forums, video sites and social media in the late 2000s, helped by how instantly recognisable the chorus is. It endures because the prank is harmless, the song is catchy, and new audiences keep discovering the trick for the first time.