INVSN (pronounced "Invasion") is a Swedish post-punk band from Umeå. Originally formed as The Lost Party as a solo project for Dennis Lyxzén, already known for the punk bands Refused and The (International) Noise Conspiracy, the project's early music was notably more folkish and softer than his prior music endeavors.

The members have all played in influential punk and rock bands from Sweden. Sara Almgren used to be in the first Swedish all-female straight-edge band The Doughnuts. She later played keyboard and guitar in The (International) Noise Conspiracy, played in bands like The Vicious and Masshysteri, and toured with Marit Bergman and Sahara Hotnights. Dennis Lyxzen is most known for being the lead vocalist in Refused but has also played in bands like The (International) Noise Conspiracy, AC4 and many more. He has also been a touring member of The Bloody Beetroots. Anders Stenberg is a member of acclaimed Swedish band the Deportees and also a touring member of Lykke Li's band. Christina Karlsson, besides playing in INVSN, also plays with bands and artist such as Frida Selander, Tiger Forest Cat and Honungsvägen. Andre Sandström hails from Swedish hardcore thrashers DS-13 and has also played with The Vicious and Ux Vileheads.