Wild-Magic Sorcerer is a rare Creature — Orc Shaman Sorcerer card from Magic Online Promos (PRM), collector number 92752.
The first spell you cast from exile each turn has cascade. (When you cast your first spell from exile, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)