The theoretical counterpart of the Meekstone. The idea is that the card's owner does not wish to damage his valuable Rare cards, and will be more than happy to replace the Changeling with the original card, as long as he doesn't have to shuffle his Rare in with the rest of the deck. When faced with a Changeling deck, it's often a good idea to examine your opponent's card collection to find out exactly how many Gaea's Leiges he really owns. I hear the National Mint has problems of this nature. Any person who doesn't play, but has more rares than you do.
Collectors are good, but essentially misguided.
Don't say we didn't warn you. To take damage. Just out of print. The story of how you got your Gaea's Leige, Lord of the Pit, Shivan Dragon or Timber Wolf. Surprisingly, mana from a different land may be used to defuse the Venom effects.