A magic slate is a quest item from Swept Away, which was released during the 2008 Hallowe'en event. It is given to players by Lottie, who is Betty's assistant. Lottie asks players to re-locate several creatures in the basement to their respective holding pens. Doing this will complete Betty's task in the Swept Away quest.
The magic slate is used to see where the holding pens are located for each creature in the basement. Once a player leaves the basement, the slate disappears.