New for 2003. Vilda Musen contains many traditional Wild Mouse-style elements such as hairpin turns and sudden drops, but there are also plenty of banked curves during the ride.

The rollercoaster was constructed to a very unusual spot, inside another one! Jetline's structure was made extra-strong when it was built, because Gröna Lund originally thought to add some mountain themeing to it. The theme never came, but they made a good use of the structure later on. To help design Vilda Musen, the park created a CAD image of Jetline's structure by placing a 3d laser measuring device to one of Extreme's arms, which created a very accurate digital representation of Jetline. But even with the 3d-model built it had to be extremely hard to place the ride inside Jetline's dense supports.

Vilda musen cost 30 million Swedish crowns to build.