PIERCES SPELL IMMUNITY:No
Puts the target enemy or friendly Hero to sleep. Sleeping units are awakened when damaged. If the target was directly attacked, the Nightmare passes to the attacking unit. Bane can attack nightmared targets freely.
In the first second of Nightmare, the unit is invulnerable.
Bane can wake himself from Nightmare.
On cast, replaced with Nightmare End: Ends all ongoing Nightmares on any affected units.