Mask of C'Thun is a Mage spell card (rarity: rare) that belongs to the "Madness at the Darkmoon Faire" set, which was released on 17.11.2020 and is one of initially 135 cards. The artist of this card was Ware Lee, who also made 13 other artworks for Hearthstone.
The card costs 7 mana and its card text reads: "Deal 10 damage randomly split among all enemies."
The flavor text of the card is the following: Hide in the mask, but it will wear you. Through its gleaming eye, you shall see true.
Based on 68 quiz answers, the card is easy to memorize: 94% of them were correct. The question on “Name” is answered correctly most often (100%), the one on “Cost” least often (84%). An answer takes 4.6 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.