Beldum (the Iron Ball Pokémon) is a rare Steel/Psychic-type Pokémon found among mountainous terrain and forested areas within the Unova region as well as the Sinnoh region on rare occasions. Though fairly useless in combat alone, Beldum are fascinating organisms whose very existence pushes the boundary between machine and life. They might not be able to do much else other than recklessly throw themselves at the opposition, but once they do manage to evolve, there won't be much stopping these little beasts from tearing apart everything that gets in their way!
To classify Beldum and their evolutions as either machines or animals would be incorrect by any standard, as they effectively occupy an area completely in the middle. Instead of blood, the circulatory systems of Beldum pump a highly-magnetized slurry of iron and metallic hydrogen kept in a liquid state by generating massive internal fields that prevent the material from solidifying. As it turns out, every single cell within Beldum is magnetized and they reproduce by replicating themselves with metallic ions absorbed from the surrounding environment. Not surprisingly, Beldum are able to levitate off the ground as a result of their intense magnetic fields, which are designed to repel from the Earth's magnetic field in order to allow them to actually move around. Moreover, they communicate with others with concentrated magnetic pulses issued directly from their frontal cortex; despite their simple operation, well over 1,000 different words have been localized from these pulses, indicating that the species has evolved a fairly complex social civilization. Although their thick skin helps to protect them against most direct attacks, Beldum still generally travel in swarms ranging from a few members to well over 100 in some cases in order to enhance their survival rate in the wild. When not moving around, Beldum rest on the edges of cliffs by hanging upside-down (much like bats) with the sharp claws on their hind quarters, which will end up serving a much more offensive purpose after evolution.
Unlike most magnetically-powered organisms, the members of the Beldum family are able to utilize their electromagnetic powers to an exceptionally advanced degree; so advanced, in fact, that they bypass the ability to utilize Electric-type attacks and are naturally able to utilize Psychic-type attacks so proficiently that they are considered to be partial Psychic-types. Sadly, Beldum are unable to utilize their own powers because their brains are unable to divert power from activating their magnetic field to actually using it as a weapon. As a result, they are only able to recklessly strike at opponents with a Take Down attack until they evolve. Since Beldum are not the most gifted of physical fighters, this can make it fairly difficult to win any battle with them if the opposition is heavily armored. Even so, Beldum evolve fairly fast despite their exceptional powers and are able to acquire a full array of attacks shortly after evolving, so their current form is effectively nothing more than a waiting game. In the meantime, Beldum are heavily protected from most direct attacks by their steel skin and are able to resist both stat changes with their Clear Body Ability (if they don’t have their hidden Ability) and capture in general, as their natural magnetic field disrupts those used by capture devices and renders them all but ineffective, making the species and its evolutions in general among the most difficult of Pokémon to capture.
While they certainly might not be built to be offensive powerhouses, Beldum are still fun little creatures that can give trainers of all kinds a real challenge in more ways than one. Though they may take a little while before they can gain access to their true powers, any trainer willing to invest in one of these odd little critters is highly unlikely to be disappointed in the long run. Just be careful not to keep them near any computers or other expensive equipment; these poor creatures have yet to gain full control over their own magnetism, and the last thing you need is to have years of research and work go down the toilet because your Beldum is affectionate!