It is said that should one ever be forced to battle Dialga, they should bring a Gothitelle, for these pokemon exist outside of Dialga's power of time. This is not entirely true, although they probably remain any trainer's best bet, for although a Gothitelle's remarkably long life is constrained by time, they can see for many thousands of years into both the past and the future.
A Gothitelle's future sight does not reach to infinity, for that would leave them insane and virtually blind; a single location simultaneously viewed through billions of years is too complex and confusing for even these pokemon's remarkable minds to process. But there is a great deal which the Gothitelle can see, from the locations of burnt-out stars and those whose light has yet to reach earth to the lives of their trainers, their ancestors, their descendants, and the entire histories of their hometowns.
Should Gothitelle freely share their knowledge with humanity, a great deal of guesswork in the physical and natural sciences would be replaced with certainty. But in most cases, they refuse to do so, for the brutality of the past often depresses these pokemon, and the future in many instances can be altered by observations. There are two exceptions to this; the first is astronomy, for nothing in the power of Man or Pokemon, even thousands of years in the future, will be able to alter the stars. The second is the source of their trainers' deaths, a haunting sight which they will do anything to avoid, but which mortality means they can never prevent. All the Gothitelle can do is keep rolling the dice until they arrive at either a long life and a death free of regret, or a tragedy which they can not stop through their warnings and powers.