Realmwalker is a rare Creature — Shapeshifter card from Secret Lair Drop (SLD), collector number 1724. Current market price: $23.41, TCGplayer market prices via Scryfall.
Changeling (This card is every creature type.) As this creature enters, choose a creature type. You may look at the top card of your library any time. You may cast creature spells of the chosen type from the top of your library.