10 Worst Decisions Harry Potter Ever Made
2. Using Sectumsempra Against Draco Malfoy
In the sixth film of the Harry Potter franchise, The Half-Blood Prince, Harry used the spell 'Sectumsempra' against Draco Malfoy. Harry had learnt the spell in his second-hand potions book but did not know the effects that the spell would have. He cast it blindly in their duel and it nearly cost Draco his life.
Sectumsempra was a spell created by Severus Snape, the Half-Blood Prince, that severely lacerated the opponent, causing excessive haemorrhaging. It nearly fatally wounded Draco Malfoy before Snape cast life saving magic to heal him.
Harry did not know what the spell's effects were, but he was driven by anger toward Draco and used it anyway. It was a brash and stupid attack that nearly turned Harry into a murderer. Without studying the spell first, Harry's decision to use it was a terrible idea.