Biriridama

Voltorb is a spherical Pokémon that resembles a buttonless Poké Ball with eyes. The top half is red, while the bottom half is white. Because of its resemblance to Poké Balls, it is thought that it was created when one was exposed to an energy pulse. This is supported by the fact that its components do not occur naturally.

Voltorb is generally found in power plants and other areas with electric fields where it feeds. It was first discovered in the plant where modern Poké Balls were invented. It has a volatile temperament and will explode if agitated or bumped by the slightest contact. Due to being constantly mistaken as a Poké Ball, Voltorb has reportedly zapped many humans as a result.

Forms
Voltorb has a regional form: Hisuian Voltorb.

Hisuian Voltorb, like its modern counterpart, resemble the Apricorn-made Poké Balls of the time period — both appear to be made of a grainy, woodlike substance, with a glossy surface and a hole on top. On the inside, Hisuian Voltorb's body contains numerous seeds, but it has been impossible to examine its interior due to it being pitch-black. Hisuian Voltorb has a distinctive red wooden unibrow. Despite its resemblance to a Poké Ball, it can be inferred that Hisuian Voltorb's existence predates the device's invention, as evidenced by the fact that the ancient hero of Hisui legend had an Electrode companion which would become the ancestor of the region's noble Electrode.

Hisuian Voltorb can store electric currents in its belly, which it discharges all at once from its hole. Unlike Kantonian Voltorb, Hisuian Voltorb have friendly and excitable temperaments, which leads them to cluster around people, causing them to be a nuisance when they discharge. It is known to let out a great, uproarious laugh whenever it discharges. There are stories of people temporarily plugging the holes of Hisuian Voltorb to prevent them from discharging before removing them from their settlements. It has been seen in Paldea during the rare Mass outbreak events.

Evolution
Voltorb evolves into Electrode.
Hisuian Voltorb evolves into Hisuian Electrode.

(Source: Bulbapedia)