X-Ray Vision is the exclusively Kryptonian ability to see through and beyond almost any solid objects, by viewing the entire electromagnetic spectrum. The extremely few objects impenetrable to Kryptonian x-ray vision are the force field of a Kryptonian Breather (when rendered opaque), and objects made of lead. Kryptonians can mentally break down the polymers layer by layer in objects and organisms, allowing them to clearly see through the object or person. With this ability Kal-El easily saw through a one-way mirror and several walls simultaneously. Since a Kryptonian's senses are inhumanly high, uncontrollable and unstable when first discovered, it can cause a Kryptonian to randomly see through objects at varying levels, which, along with their extremely powerful other senses, can initially overwhelm and agonize them, as was the case with General Zod and Faora-Ul.