Are you tired of the terrible injustice put upon adorable little house elves? Of course, you are. That’s why you’re a member of S.P.E.W.! Pour hot liquid into this black mug and your cause appears, bright and bold. Free the House-Elves! Just try not to think of Dobby on the beach … Oh, no. You’re thinking about it now, aren’t you?
The exterior of this officially licensed 11oz mug transforms from black as hot liquid is added, revealing the hidden image in full vivid colors.