“Expecto patronum!” Cast the difficult spell and let Harry’s patronus come into focus with this Morphing Mugs heat-sensitive clue mug. Add hot liquid to this mug to reveal the stag and take down more than a few Dementors in the process! Authentic Morphing Mugs Heat Sensitive Clue Mug This is the real deal. This is the legit Morphing Heat-Sensitive Clue Mug by Trend Setters Ltd. This mug looks great sitting out on display for those who like to show off their collection. Pouring hot liquid enhances the design with a surprise reveal. Perfect for gifting or collecting, drinking or displaying!