ObjectsArtifact
Blood Quill
Umbridge's punishment writing tool; it carves the words into the back of the hand as the student writes. Harry spends afternoons with 'I must not tell lies' etched into his skin, and the scar stays.
In the books
Harry Potter and the Order of the PhoenixChapter: 13
Umbridge makes Harry use the quill in detention; each line he writes cuts into the back of his hand.