system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry Potter] How fast to Bludgers move? How much damage would one do to a Muggle?
gpt
They wouldn't go after a muggle, they're charmed to go after the Quiddich players.  They move at a good clip, not quite baseball speed, but at least 20-40mph, I'd say.  You have time to react, but they're also moving enough to break through bones too.