A Spell that shorten's a unit's vision

I'm trying to make a spell that when activated will reduce enemy units' site vision to almost nothing. I don't believe there are any spells that currently do this so I believe it needs to use triggers... the only problem is I'm having trouble finding something to do this. I could use some help on this. Anybody out there know of a way with the editor? Thanks for your time.

There is no way to modify a unit sight, only if you make 2 units, and replace then with a trigger.

Actually, I found a way when I was trying to make a flare spell , only that units with life detection abilities are immune to this, you add to them an item sight bonus with a negative value

Excuse me for being such a newb, but I'm using the WC3 editor and am unable to go below 0 for the Sight Range Bonus in the Object Editor. I'm sure you can somehow so enlighten me. ^_^

(Also, can you give me a link to your Flare spell... it would probably be most helpful.)

Thanks!

to enter negative vaues you can either enable negatives in the preferences or you can shift+double click on what your editing, which will remove all limits from the field, be careful though, it could screw up the game

Thanks for the info! It is very much appreciated.

for future help on this part.. learn to use the WEUnlimit in the Tools section.. it helps ALOT!