Why did me Malfoy And mr Weasley get into a brawl?

It seems you're thinking of a specific scene from the Harry Potter series! While there are several instances of tension and conflict between the Malfoy and Weasley families, there's no specific "brawl" between Mr. Malfoy (Lucius) and Mr. Weasley (Arthur) in the books or movies.

Here's a breakdown of their conflicts:

* Diagon Alley: In *Harry Potter and the Sorcerer's Stone*, Lucius insults Arthur in Diagon Alley, mocking his job at the Ministry of Magic and his lack of wealth.

* The Chamber of Secrets: In *Harry Potter and the Chamber of Secrets*, Lucius frames Arthur for stealing the diary, further increasing the animosity between them.

* The Order of the Phoenix: In *Harry Potter and the Order of the Phoenix*, Arthur and Lucius have a tense encounter at the Ministry of Magic, but it doesn't escalate to a physical fight.

Perhaps you're thinking of a fan fiction or another interpretation of the story where a brawl between the two fathers occurs?

If you can provide more context about the brawl you're referring to, I might be able to give you a more accurate answer!