Unidentified Elixir is a Priest spell card (rarity: common) that belongs to the "Kobolds & Catacombs" set, which was released on 07.12.2017 and is one of initially 135 cards. The artist of this card was Dan Scott, who also made 45 other artworks for Hearthstone.
The card costs 3 mana and its card text reads: "Give a minion +2/+2. Gains a bonus effect in your hand."
The flavor text of the card is the following: "Here, taste this." (Slurp) "What is it?" "I don't know, I found it in one of the labs."
Based on 105 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 (91%). An answer takes 5.5 seconds on average.