Necrozma is a Pokémon whose body appears to be constructed out of black crystalline material; its disproportionately large arms have three claws jutting out of them, as well as a single large whitish crystal protruding backwards from each arm. Its small legs bend backwards like a bird's and have three toes each. However, it does not seem to use them as it can naturally levitate through unknown methods. A single wing grows out of each of its shoulders, which resembles a hook. The large protrusion attached to its head is its tail, which is white in the back with a dark gray symbol resembling a star in the center. This part of the tail absorbs light that it converts to lasers, and glows when it does. The sides of its head and the top of its tail are covered in spikes, and its face possesses a collection of multicolored shapes.
Necrozma was discovered dwelling deep underground, where it had been asleep for ages. Due to the peculiar nature of its body, the power it wields, and the rumors that it came from another world in the distant past, it is speculated that it may be related to the Ultra Beasts, if it is not actually one itself; however, the International Police have no records of it ever emerging from an Ultra Wormhole so its classification is still uncertain. Despite being pitch-black, it constantly refracts light like a prism. Light acts as the source of its energy, and it can concentrate this light to perform its signature move, Prismatic Laser. When it absorbs light, its face glows white[1]. It is known to be incredibly vicious, firing off laser beams at anything around it.
Origin
Necrozma could be based off the concept of prisms and light refraction. Given the first part of its name ("necro"), its black coloration, and the star symbol on the back of its head, it could also be based off a black dwarf (which is a theoretical "dead star" that has ceased to emit light or heat), or given its ability to absorb light, it could also be based off a black hole (which is formed from a collapsed star).
Name origin
Necrozma may be a combination of νεκρός nekrós (Ancient Greek for dead), 黒 kuro (black), and πρῖσμα prîsma (Ancient Greek for prism). It may also be based off of Project Ozma, an experiment made to search for extraterrestrial life.