The
Pokémon Pan x Pokémon Tretta x Namco Get Darkrai Campaign (ポケモンパン×ポケモントレッタ×ナムコ 「ダークライ」ゲットキャンペーン) runs in Japan from September 4th, 2014 until October 31st, 2014. Tretta players that purchase at least
two specially labeled Pokémon Pan products can trade-in the included vouchers at one of over 200 participating Namco arcade locations for a limited edition Darkrai Rookie Tretta. The exchange period is from October 3rd, 2014 until November 30th, 2014.
Limited Edition Darkrai Rookie Tretta
The Limited Edition Darkrai Rookie Tretta has: 73 Energy, 94 HP, 87 Attack, 66 Defense, 66 Speed and knows the move
Dark Pulse.
Sources:
http://www.namco.co.jp/event/pokemon/2014/darkrai-get/ and
http://www.pokemon.co.jp/info/2014/09/140904_p07.html