Amazon UK has announced that people who purchase new copies of Pokémon Black 2 and White 2 between Monday November 12th, 2012 and December 31st, 2012 will receive a unique Global Link unlock code Pikachu with Hidden Ability Lightningrod.
The offer is strictly subject to availability. One code will be issued per customer. The offer is valid when dispatched by Amazon.co.uk. Amazon reserves the right to change or terminate this promotion at any time. Codes will be dispatched via email within 48 hours of the game dispatching. Please note: Amazon cannot guarantee that codes will work on systems purchased outside of the UK.
Source:
Amazon UK
Toys R US Germany has also announced that if people purchase Pokémon Black 2 and White 2 at participating locations, they too can also get the Pikachu with Hidden Ability Lightningrod.
Get the Power of Pikachu!
Befriend an awesome Pikachu for your new Pokémon Black Version 2 or Pokémon White Version 2 game. When you pick up your Pokémon Black Version 2 or Pokémon White Version 2 game at participating Toys“R”Us stores, don’t forget to ask for a password ticket so you can get this special Pikachu! Visit the Pokémon Global Link Promotions page to enter the password and befriend the famous Pokémon. This Pikachu has the Hidden Ability Lightningrod, which draws all Electric-type moves toward Pikachu instead of their intended targets. Once you get the password, enter it at the Pokémon Global Link before May 30, 2013, to get this amazing Pikachu! You must have a copy of Pokémon Black Version 2 or Pokémon White Version 2 and must have registered its Game Sync ID at the Pokémon Global Link website to participate.
Source:
http://en.pokemon-gl.com/#/information/493