Pikachu

Pikachu is an Electric-type Pokemon. It evolves from Pichu when leveled up with high friendship, and it will evolve into Raichu when exposed to a Thunder Stone. It is the most well-known and recognizable Pokémon. Over the past several years, Pikachu has become so popular that it serves as the Pokémon franchise mascot.

Physiology
Pikachu is a small, chubby, rodent-like Pokémon which is covered almost completely by yellow fur. It has long yellow ears that are tipped with black. A Pikachu's back has two brown stripes, and its large tail is notable for being shaped like a lightning bolt. On its cheeks are two circle-shaped red pouches used for storing electricity, they turn yellow and spark with electricity when its about to use an Electric attack such as Thunderbolt. A female Pikachu looks almost exactly the same as a male, with the exception of her tail. A female Pikachu's tail is rounded at the end and has an inward dent, giving it the appearance of a heart. This, however, is only true in the Nintendo games. In the anime and in previous games, female and male Pikachu's look identical.

Like Pichu, Pikachu store most of their electricity within the red areas of their cheeks. It can be seen with small surges of electric energy whenever a Pikachu gets protective, mad, etc.

Other Appearances

 * Pikachu appears as a playable character in every Super Smash Bros. game to date.
 * Pikachu will appear as a playable character in the upcoming arcade fighting game Pokken Tournament.

Trivia

 * A Pikachu holding a Light Ball can have a higher Attack and Special Attack than its evolved form, Raichu.