Stacking Mirror Image

[kerbarian]

What happens if a character casts multiple copies of Mirror Image on himself? The general spell stacking rules don't seem to address it completely, and it's not covered in the FAQ.

The most relevant line from the rules on stacking spells seems to be:
"In cases when two or more identical spells are operating in the same area or on the same target, but at different strengths, only the best one applies."

Say a wizard cast Mirror Image on himself twice. The first casting generated 6 images and the second casting generated 5 images. So only the first casting is in effect. That's not too hard. Now a monster attacks the wizard and knocks out two of the images. Now the first casting (which was in effect) has 4 images left, and the second casting has 5 images left. Does that mean that the second casting becomes active at that point, and the wizard once again has 5 mirror images?

If so, buffing up with multiple instances of Mirror Image could be very powerful. It would take a large number of attacks to work through all the backup images, and a targeted dispel magic is likely to hit a figment and only dispel the active copy of mirror image (accidentally targeting the spell rather than the caster).

 

[Question]

I believe most DM would rule that if you cast it twice, you get the latest result only.

 

[Stalker0]

I rule that the spells overlap depending on conditions when they are first cast.

So when first cast, spell A is better than spell B, so spell A will dominate. Even if spell B becomes better than spell A, spell A is still in effect.