What exactly is the function of a rubber duck?

Professor Flitwick had dried himself off and set Seamus lines ("I am a wizard not a baboon brandishing a stick")

The idea that we could have a child who escapes from the confines of the adult world and goes somewhere where he has power, both literally and metaphorically, really appealed to me.

In opening them, he discovered that he had eyes.

Trust me," he said. "I know what I'm doing... or at least" -- he strolled confidently to the door -- "Felix does.

Which way did they go, Peeves?" Filch was saying. "Quick, tell me." "Say 'please.'" "Don't mess with me, Peeves, now where did they go?" "Shan't say nothing if you don't say please," said Peeves in his annoying singsong voice. "All right- PLEASE." "NOTHING! Ha haaa! Told you I wouldn't say nothing if you didn't say please! Ha ha! Haaaaaa!" And they heard the sound of Peeves whooshing away and Filch cursing in rage.

Raindrops the size of bullets thundered on the castle windows for days on end; the lake rose, the flower beds turned into muddy streams, and Hagrid’s pumpkins swelled to the size of garden sheds.