Explaining the Homonculous Charm with Torches

"Wait... let me do another experiment..." Vizet waved his wand and recited another spell. "Unplottable!"

He pressed the tip of his wand against his chest, and the Marauder's Map changed as well. Both "Vizet Lovegood"s vanished completely.

"Why did that happen?" Harry had even more questions now, and he asked impatiently, "Vizet, how come your... your names both disappeared?"

If they only used the names shown on the Marauder's Map to determine how many people were in this corridor, they would discover something slightly eerie—right now, only Hermione and Harry were walking through the corridor.

Hermione was concerned about another question. "Vizet, what's Ron's situation right now? Does he count as... you? Or..."

"If it's only about the Confusion Draught, you can think of him as me," Vizet said. "But in every other respect, Ron is still Ron."

He turned to Harry. "Harry, Ron mentioned something just now. Peter Pettigrew was choked until he couldn't breathe before he changed back to his original form, right?"

"Right!" Harry nodded with absolute certainty, frowning slightly as he tried hard to recall the scene at the time. "At first, he really was like a rat..."

"Until Sirius Black got very angry... angry enough that he really wanted to strangle Peter Pettigrew to death. That was when he changed back... I think he was scared!"

"Vizet, are you saying..." Hermione seemed to have thought of something. "To make Ron recover, we can transform something he's afraid of?"

"That's one method." Vizet nodded. "As for other methods... I can actively undo this... perhaps it could be called a 'covering' state."

"Let's try it?" Harry looked at Hermione and said, "Ron's afraid of spiders!"

"I know that!" Hermione drew her wand from her pocket and took out one of the sweets Dumbledore had given her. "Transfiguration