Wand Waving

What object holds the key to the secrets of the Hogwarts houses, yet its true nature remains a mystery even to the wisest witches and wizards?

What magical creature can change its appearance at will?

What is the core of a wizard's wand made from?

What magical hat at Hogwarts can read students' minds?

These magical corridors can transport you to distant parts of the castle, but to find them, you must look beyond what is seen and venture where few dare to tread. What are they?

What magical item allows the wearer to become invisible?