Insane, Steel roller coaster at Gröna Lund amusement park, Stockholm, Sweden.

Insane is a steel roller coaster at Gröna Lund amusement park that uses freely rotating cars capable of spinning in any direction throughout the ride. The track sends riders through sharp climbs and steep descents, constantly changing the perspective of what is above and below them.

Insane opened on 25 April 2009 at Gröna Lund, built by Intamin as an installation of their first-generation ZacSpin model. It was placed on the spot where the Vikingagungan swing ride had previously stood. After a deadly incident on Inferno, a coaster of the same model at Terra Mítica in Benidorm, Spain, on 7 July 2014, Gröna Lund halted Insane for several days before reopening it.

Insane takes its name from the English word for "galen" (crazy), and it stands where the Vikingagungan swing once operated. The cars hang on the side of the rails and rotate around their own axis depending on the load, so no two rides follow the same pattern. It is an installation of Intamin's first-generation ZacSpin model.

Guests must meet a minimum height requirement and should wear fitted clothing without loose items for their safety. Checking weather conditions before visiting is wise, as wind and rain can occasionally affect operations.

The passenger cars spin completely freely with no predetermined pattern, meaning each ride creates different rotations and orientations. This results in some riders finding themselves upside down while others travel sideways through the twists and turns.