This simple template can only be applied to creatures with immunity to magic (such as golems and will-o-wisps). Spell-turning creatures lose their immunity to magic, but are able to turn targeted spells back upon their casters. A spell-turning creature's quick and rebuild rules are the same.
Rebuild Rules: Immune loses immunity to magic; SR gains SR equal to CR +10; Special Attacks Spell Mirror (Su) As an immediate action, the spell-turning creature may turn a spell targeting it or a creature within its reach back on the original caster, as if the caster were the target instead of the spell-turning creature or the creature within its reach. The spell's original caster may attempt a caster level check against the spell-turning creature's spell resistance to prevent the spell from being turned. If the spell is prevented from being turned, it automatically overcomes the spell-turning creature's spell resistance.
Mirror Golem (CR 8) A mirror golem is a glass golem with the spell-turning simple template.
Mirror Golem, Frosted (CR 5) A frosted mirror golem is an ice golem with the spell-turning simple template.
Mirror Golem, Polished (CR 16) A polished mirror golem is a mithral golem with the spell-turning simple template.