Muggles love mugs - it's just a cold hard fact. You thought you'd gifted yours every Potter present going - how wrong you were!
Ignite a whole new spark of Hogwarty happiness in your favourite Gryffindor by treating them to this magical mug. Reactive to changes in temperature, when cold the mug says 'I solemly swear I am up to no good' ; when hot, it transforms to reveal Moony, Wormtail, Padfoot & Prong's Marauder's Map. Wizard!