Dialga

Dialga is a dark-blue, sauropod-like Pokémon with some gray metallic portions, such as its chest plate, which has a diamond in the center. It also has various light blue stripes. It has a fin-like structure on its back and a crest on its head, resembling a dinosaur. Dialga also has two horns on top of its head, two fang-like horns around its mouth, and three spines on the back of its neck. It has three claws on each foot of the same metallic looks as its chest plate. Faint cracks exist across its body. The wing-like structure on its back can be used to focus the flow of time.

Dialga can warp time by either speeding it up, slowing it down, or stopping it altogether. It can also travel through time to visit the past, present, and future. It is said that time started moving when Dialga was born and will continue flowing as long as Dialga's heart still beats.

(Source: Bulbapedia)