Board Thread:General Discussion/@comment-24372935-20140103014122/@comment-8168904-20140108042109

Technically, it is a glitch, since you trick the game into thinking that you don't have all level 100 Shiny Electric-type Pokemon, so I assume the game thinks that since you managed to enter the level, you obviously have all level 100 Normal Electric-type Pokemon since you don't have any shinies.

Anyways, you need to get six Shiny or Shadow Electric-types with at least one knowing Explosion or Selfdestruct as a move, preferably (and pretty much only) Electrode. Upon entering the battle against Zapdos, make one Electric-type use Selfdestruct or Explosion to remove them from battle completely. Continue until the Zapdos is defeated and the level ends. You will get a Normal Zapdos, but you are able to do this as many times as you want.

Theoretically, you can do the same in Seafoam Islands and Victory Road, but no Fire-type or Ice-type in PTD can learn Explosion or Selfdestruct.