4. Cerebro (X-Men Franchise)
Built by Professor X and Magneto when they used to be on friendly terms, Cerebro is a device for telepaths which is used almost exclusively by Professor X - as he is the only telepath powerful enough to be capable of using it safely. He uses it to expand his telepathic ability to identify mutants and humans around the world - whether he wants to learn where every single mutant or human is at any given time, or whether he wants to identify the whereabouts of a particular individual, Cerebro gives him the power to do exactly that by hooking it up to his mind. Cerebro can also kill whoever he is focusing on if Professor X were to concentrate hard enough (not that he'd want to do that). It is located in a hidden area at the X-Mansion.