Wisps of the Old Gods is a Druid spell card (rarity: epic) that belongs to the "Whispers of the Old Gods" set, which was released on 26.04.2016 and is one of initially 134 cards. The artist of this card was Skan Srisuwan, who also made 13 other artworks for Hearthstone.
The card costs 7 mana and its card text reads: "Choose One - Summon seven 1/1 Wisps; or Give your minions +2/+2."
The flavor text of the card is the following: They're just normal wisps, actually. The "Of the Old Gods" bit is just marketing.
Based on 115 quiz answers, the card is easy to memorize: 96% of them were correct. The question on “Cost” is answered correctly most often (98%), the one on “Name” least often (89%). An answer takes 7.9 seconds on average.