Siphon Soul is a Warlock spell card (rarity: rare) that belongs to the "Legacy" set. The artist of this card was Tyler Walpole, who also made 13 other artworks for Hearthstone.
The card costs 4 mana and its card text reads: "Destroy a minion. Restore 3 Health to your hero."
The flavor text of the card is the following: You probably should avoid siphoning your own soul. You might create some kind of weird infinite loop.
Based on 152 quiz answers, the card is easy to memorize: 95% of them were correct. The question on “Card text” is answered correctly most often (100%), the one on “Cost” least often (88%). An answer takes 4.9 seconds on average. In the Pixel Quiz, which shows only the shape and colour of the card, it was recognised correctly 100% of the time.