text: Players know to pick the more powerful turrets and weapons, it would be natural for aliens to do something similar.
  Biology studies indicates that Earth creatures had lots of mutation to adapt to changing climate and environmental conditions in the past, in order to survive better.
  So why can't the aliens adapt too? The cockroach-like biters and spitters are likely to mutate and/or evolve to their benefits, at least much better than any kind of mammals.
  Laser (and fire) became the main threat to them. Now some of the aliens are mutated to adapt to these threats! (Such mutations can happen, although it would have to be accelerated a lot for the in-game aliens to acquire such immunity like in this mod.)
  Disclaimer: The author is not a professional biologist. The above statements may or may not be true from the viewpoint of real biologists. Treat this as a sci-fi story to make the settings of this mod understandable. Please don't sue me if you use my statements in exam and get zero score. :-P
  In response to human laser turrets overwhelming aliens, the aliens now have a mutated variant of biters, code name "Mirror". Mirror aliens are completely immune to laser and electric (configurable in options). They would pose a high threat to your base, if your base defense has nothing more than laser turrets! You will need something extra to deal with them, like gun turrets.
  If your defense already consists of diverse types of turrets, this mod probably pose little threat to you.
  There are two mutation types: "Mirror" and "Ceramics". Both mutations only happen to big and behemoth aliens, so only affect mid to late game. Small and medium aliens do not have such mutations.
  Mirror is the codename for those aliens who have grown with laser and electric resistances. They will draw away fire from your laser turrets, covering the trailing aliens to close in.
  By default, the resistance values are both 10 / 100%, meaning they are completely immune to laser shots from laser turrets. The chances of mirror mutation are 20% (0.2) for big aliens, 30% (0.3) for behemoth aliens. All these values are fully configurable in options, under "Options" → "Mod settings" → "Startup" tab.