Ghost units (transperency): How to make 'em?

[Rektis]

Hi all.
I would like to know how you can make units which are looking like ghosts. Means: they should be transperenced.

(by using bannish or other things)

 

[AmadiTheGreat]

Animation - Set unit vertex colouring.

It's the 4th field.

 

[gavdaman88]

Or you could give them the unit ability 'etheral' but change the picture from Scotty if you control them. It saves triggers.