Exclusive! The world of Harry Potter comes alive with this I Solemnly Swear...Mischief Managed Transforming Thermal Mug. Fill this magical mug up with something hot and it turns from I Solemnly Swear That I Am Up To No Good to Mischief Managed, it also turns from black to white! Microwave safe, not dishwasher safe. Please note that this mug will come with a protective, removable clear film.