Species: speed forme deoxys

Source: https://bulbapedia.bulbagarden.net/wiki/Deoxys_(Pokémon)

Speed Forme Deoxys is the Forme of Deoxys that focuses on speed, with its other non-HP stats being average and balanced. In Gen III, it appears in this form in Pokémon Emerald.

The Speed Forme of this Pokémon has a sleek black body with thin striation. The reddish-orange skin now covers only its head, hip joints, and the area around its crystal. There is now only one tentacle on each side of its body, one red and one blue. The protrusions on its head now point upward and the back of its head now forms a long spike. There is a long, thick blue stripe running down the center of this longer protrusion. More blue stripes appear on either hip joint and on its legs.

Speed Forme Deoxys has the highest base Speed of all Pokémon.