Shadow Word: Pain is a free Priest spell card that belongs to the "Legacy" set. The artist of this card was Raymond Swanland, who also made 33 other artworks for Hearthstone.
The flavor text of the card is the following: A step up from a spell cast by many beginning acolytes: "Shadow Word: Annoy".
The card is easy to memorize with 95.69% of correct quiz questions.
