Harry had a deep impression of this Magical creature. During the exams at the end of last school year, Lupin had used Grindylows as one of the trials.
He remembered it very clearly: Vizet had directly transfigured a bridge, passing the Grindylow trial with ease in that impressive way;
Even when a Grindylow tried to attack Vizet, Vizet dealt with it using the Extraction Charm, neutralizing the Grindylow's assault.
"Grindylows!" Harry said. "I remember the Extraction Charm can be used against them."
"There's one thing you need to note..." Vizet said. "The effect the Extraction Charm produces in water is different."
"When the Extraction Charm is used underwater, the form it takes changes. It manifests as a jet of high-temperature water."
Among the combat memories Serena Pendragon had left behind, some involved fighting in water, which was why Vizet reminded Harry and the others that the Extraction Charm behaved differently underwater.
"In that case, doesn't the Extraction Charm become dangerous?" Harry analyzed. "If a Grindylow grabs your foot, and then you use that spell... you'd definitely get scalded, right?"
"No, maybe not... That effect actually seems pretty good!" he realized. "Since the Extraction Charm's effect becomes like that, we might as well use it as an attack spell!"
Cedric agreed. "Not just against Grindylows. Using the Extraction Charm against other underwater creatures should work pretty well too."
"Right! I also found a way to breathe underwater." He pushed Mediterranean Magical Aquatic Plants and Their Properties forward a little, making sure everyone could see it.
"I also really agree with Vizet's approach to solving the riddle, so we can consider bringing this along before the task begins..."
He pointed to a section in Mediterranean Magical Aquatic Plants and Their Properties. "This is an aquatic Magical Plant called 'Gillyweed'..."
There was also