Multiple choice general knowledge Viktor Krum uses this piece of magic to get into the lake for the second task. The Breathing Charm Transfiguration Charm Gillyweed Bubblehead Charm Reveal answer Fill a bubble to check yourself B Correct answer Explanation During the Second Task of the Triwizard Tournament, Viktor Krum performs a partial Transfiguration to turn his head into that of a shark. Harry uses Gillyweed, while Cedric Diggory and Fleur Delacour use the Bubble-Head Charm.