Quote Originally Posted by Myou View Post
Invisble spell from Cityscape is known to be pretty broken - +0 metamagic that can give you invisible Prismatic Spheres, blind anyone using true seeing with no save or allow you to gain permanent invisibility, which I don't think can even be dispelled.
Personally, I feel the intent is pretty obvious. The feat should not modify any lasting visible effect, magical or otherwise. Anything that lasts longer than the casting time is visible, be it damage, a magical wall or non-magical wall.