Pichu

Pichu is an Electric-type baby Pokémon introduced in Generation II. It evolves to Pikachu when its Friendship stat reaches max level.

Character description
Pichu is a very small, plump, yellow rodent-like Pokémon. It bears a similar appearance to its evolved form Pikachu, but varies in a number of ways. Pichu has diamond-shaped ears on the top of their head, with the edges being black and the interior yellow. Underneath its head is a black pattern, that somewhat resembles a collar. Its tail is completely black, and resemble a small lightning bolt, similar to its evolved forms, which are larger. Pichu also has round, pink sacs on their cheeks, used for storing electricity.

Pichu has the special ability Static. This allows for a 30% chance that an opponent will become paralyzed if it lands a physical attack on Pichu. Pichu, like its other forms, is capable of storing electricity in the pink sacs on its cheeks. Being a baby Pokémon, however, Pichu can not store as much electricity as its evolved forms. It will shock itself if any electricity leaks out of its cheeks.

As a playable character
Pichu mainly appears as an unlockable playable character in Super Smash Flash 2, as revealed on Day 4 of Super Smash Con 2017, serving as a clone of. Similarly to its appearance in Super Smash Bros. Melee, for every electric attack it deals, Pichu receives recoil damage, though unique to Super Smash Flash 2 is that once Pichu reaches 50% and above damage, it will enter its "Discharge" state, where some of its electrical attacks will deal more damage and its special moves will act differently.

As a Poké Ball Pokémon
In addition to its role as a playable character, Pichu's second role in Super Smash Flash 2 is that of a Pokémon that can be released from a Poké Ball. The Poké Ball Pichu is considerably smaller than the playable Pichu. When summoned, Pichu will charge up electricity for a short period of time and then jump up to use Thunder Wave, which creates a wide burst of electricity encompassing Pichu. It deals 13% electric damage and decent knockback to opponents hit and deals high hitstun, trapping opponents and allowing for follow-ups from the summoner. Pichu will use the move three times before disappearing.

Trivia

 * Pichu and Sandbag are currently the only characters in the  series to serve both a playable and non-playable role simultaneously.
 * Pichu is the only character to appear from a Poké Ball and also be a playable character at the same time.
 * According to developers, the Poké Ball and playable Pichu are brothers, with the Poké Ball Pichu being younger.
 * Along with Charizard, Pichu is the only character in SSF2 that can be summoned from a Poké Ball to be a playable character in the official, in its case, Super Smash Bros. Melee. However, unlike Charizard, Pichu was never a Pokémon that could be summoned from a Poké Ball. This makes Pichu the first character to truly be a playable character in the official games and turned into an assist Pokémon in the Super Smash Flash series.
 * Playable Pichu's up special move, Agility, becomes similar to Poké Ball Pichu's Thunder Wave attack when the former enters its Discharged state, sharing the same effects.