Riolu

Riolu (Japanese: リオル Riolu) is a -type Baby Pokémon introduced in Generation IV.

Physiology
Riolu is a black and blue, dog-like Pokémon nearing two and a half feet. Its appearance is similar to its evolved form Lucario, though there are some differences. Its legs and torso are colored black while its head, lower body and tail are blue. Riolu have large, rounded bumps on the backs of its forepaws, placed in a similar fashion to Lucario's spikes. Riolu also have a black "mask" with two black appendages on either side, and red eyes.

Special abilities
Riolu are sensitive to a special type of energy called Aura as Lucario is. Riolu's evolved form, Lucario, can use these waves for attacks, tracking, or to predict future moves. However, Riolu does not have the full potential of these powers, using them as described in ripples rather than waves. Moves such as Aura Sphere or Detect can not be learned by Riolu due to its inability to fully use the power of aura.

Evolution
Riolu evolves into Lucario when you level it up during the day with high friendship.

Anime
In the anime, Riolu has made an appearance during Pokémon Ranger and the Kidnapped Riolu! Parts One and Two, which aired as a one hour special commemorating the release of Pokémon Ranger: Shadows of Almia. This Riolu had been trained to use Aura Sphere and was unnaturally strong. It was taken away from its owner by a group that wanted to exploit it but Ash and co. returned it, with Kellyn's help. This Riolu developed a strong bond with Ash.

Manga
In the Pokémon Adventures manga, Maylene has a Riolu. It is seen using Drain Punch against Pearl's Monferno, who Platinum borrowed in order to fight her. Then, when Diamond's is traveling alone, he is given an egg by Riley, which eventually hatched into a Riolu. In Pokémon Diamond and Pearl Adventure! Hareta gained a Riolu egg in Serious Training on Iron Island which hatched into a Riolu later on in that chapter.

Trivia

 * Riolu is the only pure -type Pokémon whose evolved form is not a pure -type, but instead a and .
 * Both of Riolu's abilities have something to do with flinching. Steadfast increases Riolu's speed when it flinches while Inner Focus prevents it from flinching.
 * This means, that in the Pokémon Mystery Dungeon Series where Pokémon have both of their abilities, Inner Focus prevents Steadfast from ever activating.
 * Riolu is the only Fighting Pokémon playable in Pokémon Mystery Dungeon: Explorers of Sky.

Origins
Riolu's name is simply based on Lucario's name, switching "Rio" with "Lu" and leaving out "Ca".