"Brain Wrap" is actually a lead-osmium alloy, pressed into thin sheets and stored as rolls of a foil-like substance. Made out of two of the densest materials on Earth, this alloy foil was used in Ancient Days as a spacecraft insulator for its ability to stop most forms of radiation and cosmic rays, as well as microscopic particles. It was also used to line reactor chambers, hazmat suits, and other places where hazardous energies were present. It wasn't until the days after the Apocalygeddon that some clever mutant discovered it could also protect against mental energies as well.
If Brain Wrap is wrapped around the cranium of a mutant, it effectively protects the mutant from all mental attacks. Their minds cannot be read. They cannot be possessed or manipulated. They cannot be controlled and they will not be fooled by mental illusions. They are, in effect, immune to any direct mind attacks from another mutant. However, the same is true for the Wrap-wearing mutant. They will be unable to use any of their own mental mutations while wearing Brain Wrap.
Some mutants may get the bright idea to wear Brain Wrap all of the time as a form of mental combat protection. This plan is doomed to fail for the following reasons:
- Although dense, Brain Wrap is very thin and easily torn. The slightest tear will render the Brain Wrap ineffective. (The ML should roll a save every time the mutant does anything to potentially tear the fragile material.)
- Wearing Brain Wrap is like having a wet towel wrapped around your head. It's heavy, awkward, and uncomfortable. It also is hard to keep in place if the wearer is actively moving around a lot.
- Brain Wrap is ineffective unless it is making physical contact with the cranium of the user. Also, it loses its effectiveness if it is covered in some manner. In other words, lining a helmet with it will not work.
- Because Brain Wrap absorbs energies rather than deflecting them, that roll of Ancient lead-osmium foil could have been used in a leaking reactor and thus be contaminated by lethal amounts of radiation. Wrapping your head with radiation-emitting foil is a "bad thing."