Eternatus

Eternatus is a gigantic alien dragon. Its body has a vaguely draconic shape and a skeletal appearance, and is largely dark violet with red highlights. Its main body and tail are long, thin, and resemble a spinal column, and it has four small, thin limbs ending in claws formed from spindly appendages attached at right angles. Its torso is formed from a cage of appendages resembling ribs, and inside is a glowing pink core that serves as Eternatus's energy source, absorbing energy to sustain it. The core can also project its absorbed energy into massive blasts. Its head is triangular in shape and has a pair of white, eye-like markings in the form of three connected circles, as well as a spindly lower jaw with several diamond-shaped teeth. Over its head is a translucent red film held between five long spikes extending toward its body's rear. It also has a pair of thin tendrils extending from its back, formed from numerous triangular segments. Eternatus's gigantic size makes it the tallest known Pokémon to ever exist.

If Eternatus absorbs a massive amount of energy at once, it will enter its Eternamax form, becoming far larger in size. Eternatus will also briefly enter this form when using its signature move Eternabeam. In this form, Eternatus's shape drastically changes. Its body becomes incredibly long and serpentine with most of its body forming a massive coil. Its entire body glows red in this form, and present at regular intervals across its length are black rings with spikes extending outward. Its back tendrils now curl around its main body. Its energy core rests at the center of the coil inside a cage of violet spikes. Eternatus's head takes on the form of a giant hand, with its fingers covered in black armor with spikes extending from the back of each segment. At the tip of each finger is a glowing pink eye.

Eternatus serves as the source of the Dynamax and Gigantamax phenomena in Galar due to its power leaking out in the form of Galar Particles following its defeat thousands of years ago by Zacian and Zamazenta. Pieces of its body imbued with its power rain down throughout Galar in the form of Wishing Pieces, Wishing Chips and Wishing Stars. When it is awake, Eternatus causes a phenomenon dubbed the Darkest Day, in which the massive quantities of Dynamax energy it unleashes causes Pokémon to Dynamax and rampage uncontrollably. Despite this, it cannot be Dynamaxed itself as its Eternamax form replaces that effect.

In its Eternamax form, Eternatus's power grows so immense that it causes a great storm of Dynamax energy around it, ripping holes in spacetime in the midst of the storm as it releases a virtually infinite amount of energy. Its tremendous power can even prevent opposing Pokémon from attacking it as it gathers energy.

Eternatus is an extraterrestrial Pokémon that came to Earth inside a meteor around 20,000 years ago.

Eternatus is the only known Pokémon capable of using Dynamax Cannon and Eternabeam.