(All information from Bulbapedia)

PIKACHU!

  • Niue released a one-dollar coin featuring Pikachu as part of a commemorative promotion for the Pokèmon franchise, with Pikachu on one side and the nation's coat of arms on the other.
  • Pikachu and its evolved form share their category with Rattata, Raticate, Sandshrew and Sandslash. They are all known as the mouse Pokèmon.
  • Veronica Taylor has stater that Pikachu is her favourite Pokèmon. Sarah Natochenny has said it was her favouriter as well, along with Mew.
  • In 2008, Japanese researchers discovered a new protein that helps carry electrical impulses from the eyes to the brain and named it Pikachurin. According to the researchers, the decision was based on both the Pokèmon and protein possessing "lightning fast moves and shocking electric effects."
  • There have been three Pikachu balloons in the Macy's Thanksgiving Day Parade. The first, known as the "flying Pikachu" was flown from 2001 through to 2005. It was used in a morning rush hour test of wind conditions in Times Square after an accident involving an M&M's balloon in the 2005 parade and made it's farewell at the Party of the Decade in August 2006, in New York's Bryant Park. The second version debuted in the 2006 parade, featuring a new Pikachu with glowing cheeks, while chasing a Pokèball. The third one, introduced for the 2014 parade, has Pikachu wearing a green scarf and holding a small Pikachu shape snow man.
  • Pikachu is one of fourteen Pokèmon that can collect foreign Pokèdex entries in Pokèmon Diamond & Pearl.
  • The earliest depictions of Pikachu had differently coloured bellies, most notably the sprites for Pokèmon Red, Green and Blue, as well as the international Red and Blue.
  • Pikachu is the only core series starter Pokèmon with a pre-evolved form, though Pichu was not available in Pokèmon Yellow.
  • Pikachu is the only core series starter Pokèmon that is not Fire, Water or Grass Type.
  • According to 'A Sneak Peek at Pokèmon; Pikachu can deliver a constant current of 1000 amperes.
  • As of Generation V, Pikachu has the most event exclusive moves available to it.
  • In the Japanese Pokèmon Yellow, X, Y, Omega Ruby and Alpha Sapphire, Pikachu uses its cry from the anime as voiced by Ikue Otani. Pikachu is the only Pokèmon that uses its anime voice in any core series game.
  • In all of these games, Pikachu's cry upon entering the field is not the same cry played in its status or Pokèdex screens.
  • If the starter Pikachu from Yellow is transferred to Pokèmon Stadium or Stadium 2, it will also use its anime voice.
  • Black, White, Black 2 and White 2 are the only core series, handheld games in which Pikachu is not available in some way, although it makes a number of cameo appearances including as an NPC.
  • Pikachu was the focus of a Pokèmon Center collection in June 2014.