Aurorus is a quadruped, dinosaurian Pokémon that resembles a sauropod. It is primarily blue with a lighter 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 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 kindly in nature, but has the ability to create ice walls or encase enemies in ice. The crystals on its body produce freezing air as cold as -240 degrees Fahrenheit (-150 degrees Celsius).
Aurorus is based on a sauropod dinosaur, and bears a strong resemblance to the Amargasaurus, which were speculated to have possible skin sail extensions on their vertebral spines. It also shares traits with various species of Diplodocoidea. The 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.