Fascinate

The fascinated unit can pass through inaccessible terrain

 

Such as? Like, actual "inaccessible" terrain? Can you provide some more specifics?

 

Yes, inaccessible. Not impassible.
Opponents Dark Seductress fascinated my Wailing Banshee through inaccessible terrain in Darkmarsh map.
The lucky thing is, wailing banshee went through it, instead of getting stuck in it.

 

Was the Wailing Banshee Flying at the time?

 

Can't recall, doubt so.