Here's why:
* The Gamestop Jirachi was a special event distribution. It wasn't available through codes or other means. You could only get it by visiting a participating Gamestop store during a specific time period.
* Event Pokemon are tied to the game's internal clock and the distribution date. This means even if you had a code, it wouldn't work because the event window is long closed.
The only way to obtain this specific Jirachi now would be to:
* Trade for one from someone who still has it. Be wary of scams and make sure the trade is legitimate.
* Use a hacked game. However, using hacked games can be risky and is against the spirit of the game.
Remember, playing fairly and ethically is always the best way to enjoy the Pokemon games.