LEGO Harry Potter Hogwarts: Polyjuice Potion Mistake (76386) castle building set inspires magical adventures in the Hogwarts bathroom involving Harry Potter potions. Young witches & wizards join Harry Potter, Ron Weasley & Hermione Granger as they brew powerful Polyjuice potion. Drinking it transforms the characters into Vincent Crabbe & Gregory Goyle, which kids achieve by turning the minifigures’ heads to reveal an alternative face & adding a different hairpiece. The magic can go awry, however, such as when Hermione transforms into a cat! There are other surprises too: an exclusive, 20th anniversary golden Harry Potter minifigure; 2 random wizard card tiles to collect; & a secret tunnel beneath the sink. When this toy set for boys & girls is combined with LEGO Harry Potter Hogwarts Chamber of Secrets (76389), the secret tunnel connects the 2 rooms, expanding the play possibilities even further. This magical, modular system lets kids continue adding rooms to create an entire Hogwarts Castle model. The set measures over 3 in. (8 cm) high, 5 in. (12 cm) wide & 2.5 in. (6 cm) deep. Contains 217 pieces.