Cho-Arrim Alchemist is a rare Creature — Human Spellshaper card from Mercadian Masques (MMQ), collector number 8. Current market price: $0.53 (foil $7.97), TCGplayer market prices via Scryfall.
{1}{W}{W}, {T}, Discard a card: The next time a source of your choice would deal damage to you this turn, prevent that damage. You gain life equal to the damage prevented this way.