Crucio

Target creature gets -X/-X until end of turn,
where X is the the target's power and toughness
minus one.
The pain was so intense, so all-consuming, that Harry no longer knew where he was. . . .
White-hot knives were piercing every inch of his skin,
his head was surely going to burst with
pain, he was screaming more loudly than he'd
ever screamed in his life--