Aurorus

Aurorus (meaning "Aurora lizard"アマルルガ Amaruruga) is a Rock-Ice-type Fossil Pokémon introduced in Generation VI. It is Tyrantrum's counterpart.

https://vignette.wikia.nocookie.net/pokemon/images/9/9e/699Aurorus.png/revision/latest?cb=20140329055732

Physiology
Aurorus is a huge dinosaur-like Pokémon bearing resemblance to the Amargasaurus, with light blue colored skin, a teal stomach, and blue eyes. It has many icy gems on the sides of its body and a long, curled tail. When it emits a cry, the thin blue-tipped membrane on its head ripples with a light green color, while it attacks, the membrane turns orange. With the icy crystals that line its sides, Aurorus can freeze the surrounding air and trap its foes in ice.

Evolution
Aurorus is an evolved form of Amaura, by leveling up to 39 or above at night.

Anime
Thaddeus' Aurorus

Trivia

 * No Pokémon other than Aurorus and its pre-evolution Amaura has unique type matchup of rock/ice.
 * Aurorus is the tallest Fossil Pokémon.

Origin
Aurorus is based on the Sauropod dinosaur, Amargasaurus and also might be based on Aurora Borealis.

Etymology
Aurorus' name comes from "aurora" and the suffix "saurus" which is used to describe dinosaurs.