Well, I went to a store to buy a LM pack, and I walked happily home. When I came home, I opened the pack, and I got VERY surprised with what popped out of it. A Walrein ex, a Gengar and a Dustox ex, same pack. What are the odds for this?
Suprisingly, a very similar thing happened to me. But it's a long story.
Things like that are usually a mistake. Like this guy on the forums said he got all commons in a pack. So, if one of those pokemon was a reverse foil, then one of the other cards would have to be a mistake.
That sort of stuff does happen from time to time. One of my friends at our league got some Celebi promos from the 4th movie. We each got one. Much to my surprise, the pack that I got had 2 of them. So I have 2 Celebi promo (which is actually Modified legal!!).
Stuff like this is pretty rare; I've bought several boxes of cards (1 for each set) ever since Unseen Forces, and I have never had something like that happen to me. The only exception to the rule happened during Jungle, when I pulled a Pikachu Promo 1st edition. That card is easily the rarest card I have.
maybe it's a special pack, which Nintendo made to make someone lucky
like, I used to play DBZ TGC, and some packs (1/5 boxes) where all holo, and I got 2 of those packs, but i never had that much luck with Pokémon