What exactly happens when Invisibility is being cast on a unit?

[Deserted]

When a sorceress casts Invisibility on a unit, it is forced to stop attacking in some special way.

I want to do the same via triggers. Is this possible?

 

[BloodSoul]

Yes. Add "Cargo Hold (Orc Burrow)" ability to a unit. Then remove it, rendering the unit able to attack again. Do note that the "Attack" button will disappear from the command card while a unit possesses the "Cargo Hold" ability.

 

[LordDz]

Drunken Haze and Silence can also be modified to have the effect to remove attack from a unit.