After a brief chat, Dumbledore sent Harry back to rest, while Su Er stayed behind.
Not long after Harry left, Su Er voiced the question that had been lingering in his mind.
"Professor, how did Harry become a Horcrux?"
"That has to do with how Horcruxes are made." Dumbledore rose from the sofa and walked over to a cabinet in the corner of the Headmaster's Office. "Before I answer that question, let us watch a memory."
This was not Su Er's first time using the Pensieve. After waiting for Dumbledore to pour the silvery strands into the swirling, misty liquid, Su Er dipped his head into it with practiced ease.
The world spun around him, and by the time he landed, the scene before him had changed.
A wand appeared before Su Er, its tip sending out multicolored streamers. Amid a tinkling sound, he followed the wand with his eyes and saw a plus-sized version of Harry Potter.
"This is Godric's Hollow. That is James, Harry's father." Dumbledore's voice sounded beside Su Er's ear.
Su Er's gaze immediately grew complicated. "Then this memory is..."
"Yes." There was guilt in Dumbledore's voice.
They were in a sitting room, neither spacious nor lavish, but every corner bore signs of careful arrangement. A great deal of thought had clearly gone into it, giving it a warm, cozy feel.
James stood beside a cot, using magic to amuse a chubby, black-haired boy dressed in pale blue pajamas.
So this is Harry... Su Er understood.
Harry laughed as he reached out to catch the streamers, but whenever they touched his chubby little hands, they turned into smoke and vanished.
Above the cot, a miniature broom floated in circles, a bell tied to its tail. That was where the tinkling Su Er had heard came from.