Help with my spell (spell immunity problem)

Help with my spell (spell immunity problem)

My spell is petrify where it turns a unit into stone (just turns grey and freezes the target) but I am having problems. You are able to cast it again on the unit that you targeted and it does the same thing!! I tryed giving the unit spell immunity but you can still cast petrify on it. I still want to have spell immunity because stones reflect magic.I even changed the base ability but it STILL doesn't work. If you know what is wrong please post it here and tell me.

Thank You.

Well... I dunno the problem, but I think I know a solution to the recasting problem.

When it turns a unit grey, add that unit to a unit group
When the trigger is called, check to make sure the unit is not in the unit group.
When the effect ends, remove that unot frpm the unit group.

Or just make the cooldown longer then the effect.

I'll take a stab at it. What ability is your spell based off? Certain abilities ignore spell immunity (i.e. Charm and Finger of Death.)

Also, is your ability triggered? If so, post the triggers.

~The_Raven

Never mind I found out the problem. I paused the unit then made it spell immune, not the other way round. Thanks for your help though.