Invisibility Purge

Ranged spell
Daily
Target: 
Any nearby enemies who are invisible, whether you know they are there or not
Attack: 
Intelligence + Level vs. MD, rolled by GM
Hit: 
The target turns visible and cannot become invisible again this battle.
Miss: 
If there are one or more invisible creatures nearby, you become aware of their presence. Not where they are, or who they are, but that there are invisible creatures present.
9th Level Spell: 
The spell also affects far away targets that you could normally see.