Aurorus is a quadrupedal, dinosaurian Pokémon that resembles a sauropod. It is primarily blue with a light blue underside. It has bright blue eyes, a long neck, and a long, tapering tail with a teardrop-shaped tip. On its head is a V-shaped white marking with a single, light blue crystal in the center. Two large, flowing sails extend from the top of its head and run down the length of its neck. The sails are pale whitish-yellow at the base and fade into a pale bluish-purple at the edges. However, its sails can change color depending on its mood as seen in Pokémon-Amie. Running the length of its body on either side is a line of small ice crystals. There are three clawed toes on its hind legs, but one large nail and a single claw on its forelegs.
Aurorus is usually quiet and kind, but can create ice walls or encase enemies in ice when enraged. The crystals on its body produce freezing air as cold as -240 degrees Fahrenheit (-150 degrees Celsius). One Aurorus was discovered frozen in a glacier as it looked a long time ago. It is said that when Aurorus howls, several auroras will then appear in the sky.
Aurorus has the highest base HP stat of all Rock-type Pokémon.
Aurorus shares several aspects with Tyrantrum. Both are Rock-type Pokémon introduced in Generation VI. Both of them evolve starting at level 39 from a Pokémon with a base stat total of 362, although Aurorus evolves at night rather than during the day. Both also share a base stat total of 521.
On March 26, 2022, Ariga commented on a paper released two days prior that supports the hypothesis that the Amargasaurus had a sail on its neck, similar to Aurorus, instead of keratinized spikes.
Aurorus is based on a sauropod dinosaur, specifically the Amargasaurus, which were speculated to have possible skin sail extensions on their vertebral spines. According to designer Hitoshi Ariga, he decided to design Pokémon based on sauropods to pair with the Tyrannosaurus-derived Tyrantrum, and Amargasaurus was chosen as a base to differentiate it from other long-necked dinosaur-like Pokémon such as Lapras, Meganium, or Deino. Ariga decided to design Aurorus with its neck having a sail instead of keratinized spikes, seen in some reconstructions of Amargasaurus, out of personal preference. Aurorus also shares traits with various other species of Diplodocoidea (a classification of sauropods which includes Amargasaurus).
Aurorus's color-changing sails are also based on auroras, most likely aurora borealis due to its partial Ice typing, and the fact it only evolves at night, when the aurora borealis is most often seen. Similar to Tyrantrum, considering its white, V-shaped mark with an ice crystal covering the top of its head and two flowing extended sails running down its neck, it may have also been based upon a queen, with the mark and the two flowing sails acting as a tiara or a headdress worn by queens from medieval times while its body with small ice crystals resembles a dress.
Aurorus may be a combination of aurora and Amargasaurus.