LEGO Harry Potter | Cauldron: Secret Potions Classroom 76464. Build a magical cauldron that opens to reveal a hidden Potions classroom with removable tables, ingredients and bottles. Includes Professor Snape and Hermione Granger minifigures, Hermione’s otter Patronus and a Hogwarts portrait. The cauldron measures approximately 20 cm high, 14 cm wide and 13 cm deep.