Banshee

Banshee is a dangerous hostile creature that spawn in all worlds through monsters portals in multiplayer games. She is a ghost and can pass through walls. She attacks dwarfs spreading an aura that makes dwarfs very slow.

Tips
As banshees make dwarfs' movement harder and as they have few health points, it is recommended to kill them before all other monsters in the wave. Mages with their long range are good at this job.