Draco Malfoy taunts Harry, foreshadowing trouble

Draco Malfoy interrupts the compartment with Crabbe and Goyle, taunting Harry about being second-best to Ron. Malfoy, now a prefect, threatens to keep an eye on Harry and report any misconduct. Hermione quickly intervenes, and the trio grows uneasy about Malfoy's new authority and his potential for causing trouble.