And about the pokemon: Maybe you know a Trading Card Game? Magic:The Gathering, Pokemon, YuGiOh, Duel Masters, ... There are many of them, and in most of them there are cards that are printed "shiny"/"foil"/"holographic" or whatsoever

And of course those cards are much rarer than normal ones. For example in Magic (see above) one out of 70 cards is a foil card, or in Pokemon TCG the shiny cards are an own rarity - the rarest one