Complex sentence: Pansy first appears in "Harry Potter and the Philosopher's Stone" at the broom flying class during which she teases Parvati Patil who defended Neville Longbottom when Draco throws away his Remembrall.
Split into simpler sentences: Pansy first appears in "Harry Potter and the Philosopher's Stone" at the broom flying class. During it, she teases Parvati Patil who defended Neville Longbottom when Draco throws away his Remembrall.